drm/dp_mst: switch from drm_debug_printer() to device specific drm_dbg_printer()

Prefer the device specific debug printer.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/50d510a6e13735cef10325742bf49b7f6955b970.1705410327.git.jani.nikula@intel.com

drm/dp_mst: Separate @failing_port list in drm_dp_mst_atomic_check_mgr() comment

Stephen Rothwell reported htmldocs warnings when merging drm-intel
tree:

Documentation/gpu/drm-kms-helpers:296: drivers/gpu/drm/display/drm_dp_mst_topology.c:5484: ERROR: Unexpected indentation.
Documentation/gpu/drm-kms-helpers:296: drivers/gpu/drm/display/drm_dp_mst_topology.c:5488: WARNING: Block quote ends without a blank line; unexpected unindent.

Separate @failing_port return value list by surrounding it with a
blank line to fix above warnings.

Fixes: 1cd0a5ea427931 ("drm/dp_mst: Factor out a helper to check the atomic state of a topology manager")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20231114141715.6f435118@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231114081033.27343-1-bagasdotme@gmail.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drm: remove I2C_CLASS_DDC support

After removal of the legacy EEPROM driver and I2C_CLASS_DDC support in
olpc_dcon there's no i2c client driver left supporting I2C_CLASS_DDC.
Class-based device auto-detection is a legacy mechanism and shouldn't
be used in new code. So we can remove this class completely now.

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drm/dp_mst: Fix PBN divider calculation for UHBR rates

The current way of calculating the pbn_div value, the link BW per each
MTP slot, worked only for DP 1.4 link rates. Fix things up for UHBR
rates calculating with the correct channel coding efficiency based on
the link rate.

v2:
- Return the fractional pbn_div value from drm_dp_get_vc_payload_bw().
v3:
- Fix rounding up quotient while calculating req_slots. (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231117150929.1767227-1-imre.deak@intel.com

drm/dp_mst: Store the MST PBN divider value in fixed point format

On UHBR links the PBN divider is a fractional number, accordingly store
it in fixed point format. For now drm_dp_get_vc_payload_bw() always
returns a whole number and all callers will use only the integer part of
it which should preserve the current behavior. The next patch will fix
drm_dp_get_vc_payload_bw() for UHBR rates returning a fractional number
for those (also accounting for the channel coding efficiency correctly).

Cc: Lyude Paul <lyude@redhat.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Wayne Lin <wayne.lin@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[Rebased changes in dm_helpers_construct_old_payload() on drm-intel-next]
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231116131841.1588781-2-imre.deak@intel.com

drm/dp: Add helpers to calculate the link BW overhead

Add helpers drivers can use to calculate the BW allocation overhead -
due to SSC, FEC, DSC and data alignment on symbol cycles - and the
channel coding efficiency - due to the 8b/10b, 128b/132b encoding. On
128b/132b links the FEC overhead is part of the coding efficiency, so
not accounted for in the BW allocation overhead.

The drivers can use these functions to calculate a ratio, controlling
the stream symbol insertion rate of the source device in each SST TU
or MST MTP frame. Drivers can calculate this

m/n = (pixel_data_rate * drm_dp_bw_overhead()) /
(link_data_rate * drm_dp_bw_channel_coding_efficiency())

ratio for a given link and pixel stream and with that the

slots_per_mtp = CEIL(64 * m / n)

allocated slots per MTP for the stream in a link frame and with
that the

pbn = slots_per_mtp * drm_mst_get_pbn_divider()

allocated PBNs for the stream on the MST link path.

Take drm_dp_bw_overhead() into use in drm_dp_calc_pbn_mode(), for
drivers calculating the PBN value directly.

v2:
- Add dockbook description to drm_dp_bw_channel_coding_efficiency().
(LKP).
- Clarify the way m/n ratio is calculated in the commit log.
v3:
- Fix compile breakage for !CONFIG_BACKLIGHT_CLASS_DEVICE. (LKP)
- Account for FEC_PM overhead (+ 0.0015625 %), add comment
with the formula to calculate the total FEC overhead. (Ville)
v4:
- Rename DRM_DP_OVERHEAD_SSC to DRM_DP_OVERHEAD_SSC_REF_CLK. (Ville)
v5:
- Clarify in the commit log what MTP means.
- Simplify the commit log's formula to calculate PBN.

Cc: Lyude Paul <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: kernel test robot <lkp@intel.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> (v2)
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231107001505.3370108-1-imre.deak@intel.com

drm/dp_mst: Allow DSC in any Synaptics last branch device

The Synaptics MST branch devices support DSC decompression on all their
output ports, provided that they are last branch devices (with their
output ports connected to the sinks). The Thinkpad 40B0 TBT dock for
instance has two such branch devices, a secondary one connected to one
of the output ports of the primary; hence the decompression needs to be
enabled in both branch devices to enable decompression for all the
sinks.

Based on the above add support for enabling decompression in last
Synaptics branch devices.

Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-7-imre.deak@intel.com

drm/dp_mst: Swap the order of checking root vs. non-root port BW limitations

drm_dp_mst_atomic_check_mgr() should check for BW limitation starting
from sink ports continuing towards the root port, so that drivers can
use the @failing_port returned to resolve a BW overallocation in an
ideal way. For instance from streams A,B,C in a topology A,B going
through @failing_port and C not going through it, a BW overallocation of
A,B due to a limit of the port must be resolved first before considering
the limits of other ports closer to the root port. This way can avoid
reducing the BW of stream C unnecessarily due to a BW limit closer to the
root port.

Based on the above swap the order of the BW check for the root port and
the check for all the ports downstream of it (the latter going through
the topology already in the sink->root port direction).

Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-6-imre.deak@intel.com

drm/dp_mst: Factor out a helper to check the atomic state of a topology manager

Factor out a helper to check the atomic state for one MST topology
manager, returning the MST port where the BW limit check has failed.
This will be used in a follow-up patch by the i915 driver to improve the
BW sharing between MST streams.

Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-5-imre.deak@intel.com

drm/dp_mst: Add helper to determine if an MST port is downstream of another port

Add drm_dp_mst_port_downstream_of_parent() required by the i915
driver in a follow-up patch to resolve a BW overallocation of MST
streams going through a given MST port.

Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-4-imre.deak@intel.com

drm/dp_mst: Fix fractional DSC bpp handling

The current code does '(bpp << 4) / 16' in the MST PBN
calculation, but that is just the same as 'bpp' so the
DSC codepath achieves absolutely nothing. Fix it up so that
the fractional part of the bpp value is actually used instead
of truncated away. 64*1006 has enough zero lsbs that we can
just shift that down in the dividend and thus still manage
to stick to a 32bit divisor.

And while touching this, let's just make the whole thing more
straightforward by making the passed in bpp value .4 binary
fixed point always, instead of having to pass in different
things based on whether DSC is enabled or not.

v2:
- Fix DSC kunit test cases.

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: David Francis <David.Francis@amd.com>
Cc: Mikita Lipski <mikita.lipski@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Fixes: dc48529fb14e ("drm/dp_mst: Add PBN calculation for DSC modes")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[Imre: Fix kunit test cases]
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-3-imre.deak@intel.com

drm/dp_mst: Tune down error message during payload addition

If a sink is removed in the middle of payload addition the corresponding
AUX transfer will fail as expected, so tune the error message down to a
debug messge.

Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230913223218.540365-3-imre.deak@intel.com

drm/dp_mst: Sanitize error return during payload addition

Return an error during payload addition if the payload port isn't
found. This shouldn't change the behavior since only the i915 driver
checks the return value, printing an error message in case of a failure.

While at it simplify the control flow.

Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230913223218.540365-2-imre.deak@intel.com

drm/dp_mst: Fix NULL dereference during payload addition

Fix the NULL dereference leading to the following stack trace:

[ 129.687181] i915 0000:00:02.0: [drm:drm_dp_add_payload_part1 [drm_display_helper]] VCPI 1 for port 000000005be4423e not in topology, not creating a payload to remote
[ 129.687257] BUG: kernel NULL pointer dereference, address: 0000000000000560
[ 129.694276] #PF: supervisor read access in kernel mode
[ 129.699459] #PF: error_code(0x0000) - not-present page
[ 129.704612] PGD 0 P4D 0
[ 129.707178] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 129.711556] CPU: 2 PID: 1623 Comm: Xorg Tainted: G U 6.6.0-rc1-imre+ #985
[ 129.719744] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR5 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023
[ 129.732509] RIP: 0010:drm_dp_mst_topology_put_port+0x19/0x170 [drm_display_helper]
[ 129.740111] Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 89 fb 48 83 ec 08 <48> 8b 87 60 05 00 00 44 8b 0f 48 8b 70 58 41 83 e9 01 48 85 f6 74
[ 129.758842] RSP: 0018:ffffc90001daf900 EFLAGS: 00010286
[ 129.764104] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
[ 129.771246] RDX: 0000000000000000 RSI: ffffffff9e73d613 RDI: 0000000000000000
[ 129.778394] RBP: ffffc90001daf930 R08: 0000000000000000 R09: 0000000000000020
[ 129.785533] R10: 0000000000ffff10 R11: 000000000000000f R12: ffff888116c65e40
[ 129.792680] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 129.799822] FS: 00007f39f74b1a80(0000) GS:ffff88840f680000(0000) knlGS:0000000000000000
[ 129.807913] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 129.813670] CR2: 0000000000000560 CR3: 0000000138b88000 CR4: 0000000000750ee0
[ 129.820815] PKRU: 55555554
[ 129.823551] Call Trace:
[ 129.826022] <TASK>
[ 129.828154] ? show_regs+0x65/0x70
[ 129.831599] ? __die+0x24/0x70
[ 129.834683] ? page_fault_oops+0x160/0x480
[ 129.838824] ? dev_printk_emit+0x83/0xb0
[ 129.842797] ? do_user_addr_fault+0x2e2/0x680
[ 129.847175] ? exc_page_fault+0x78/0x180
[ 129.851143] ? asm_exc_page_fault+0x27/0x30
[ 129.855353] ? drm_dp_mst_topology_put_port+0x19/0x170 [drm_display_helper]
[ 129.862354] drm_dp_add_payload_part1+0x85/0x100 [drm_display_helper]
[ 129.868832] intel_mst_pre_enable_dp+0x1ef/0x240 [i915]
[ 129.874170] intel_encoders_pre_enable+0x83/0xa0 [i915]
[ 129.879524] hsw_crtc_enable+0xbe/0x750 [i915]
[ 129.884095] intel_enable_crtc+0x68/0xa0 [i915]
[ 129.888752] skl_commit_modeset_enables+0x2c4/0x5d0 [i915]
[ 129.894365] intel_atomic_commit_tail+0x765/0x1070 [i915]
[ 129.899885] intel_atomic_commit+0x3ba/0x400 [i915]
[ 129.904892] drm_atomic_commit+0x96/0xd0 [drm]
[ 129.909405] ? __pfx___drm_printfn_info+0x10/0x10 [drm]
[ 129.914698] drm_atomic_helper_set_config+0x7e/0xc0 [drm_kms_helper]
[ 129.921102] drm_mode_setcrtc+0x5af/0x8d0 [drm]
[ 129.925695] ? __pfx_drm_mode_setcrtc+0x10/0x10 [drm]
[ 129.930810] drm_ioctl_kernel+0xc4/0x170 [drm]
[ 129.935317] drm_ioctl+0x2a4/0x520 [drm]
[ 129.939305] ? __pfx_drm_mode_setcrtc+0x10/0x10 [drm]
[ 129.944415] ? __fget_light+0xa5/0x110
[ 129.948212] __x64_sys_ioctl+0x98/0xd0
[ 129.951985] do_syscall_64+0x37/0x90
[ 129.955581] entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Fixes: 5aa1dfcdf0a4 ("drm/mst: Refactor the flow for payload allocation/removement")
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230913223218.540365-1-imre.deak@intel.com

drm/mst: Refactor the flow for payload allocation/removement

[Why]
Today, the allocation/deallocation steps and status is a bit unclear.

For instance, payload->vc_start_slot = -1 stands for "the failure of
updating DPCD payload ID table" and can also represent as "payload is not
allocated yet". These two cases should be handled differently and hence
better to distinguish them for better understanding.

[How]
Define enumeration - ALLOCATION_LOCAL, ALLOCATION_DFP and ALLOCATION_REMOTE
to distinguish different allocation status. Adjust the code to handle
different status accordingly for better understanding the sequence of
payload allocation and payload removement.

For payload creation, the procedure should look like this:
DRM part 1:
* step 1 - update sw mst mgr variables to add a new payload
* step 2 - add payload at immediate DFP DPCD payload table

Driver:
* Add new payload in HW and sync up with DFP by sending ACT

DRM Part 2:
* Send ALLOCATE_PAYLOAD sideband message to allocate bandwidth along the
virtual channel.

And as for payload removement, the procedure should look like this:
DRM part 1:
* step 1 - Send ALLOCATE_PAYLOAD sideband message to release bandwidth
along the virtual channel
* step 2 - Clear payload allocation at immediate DFP DPCD payload table

Driver:
* Remove the payload in HW and sync up with DFP by sending ACT

DRM part 2:
* update sw mst mgr variables to remove the payload

Note that it's fine to fail when communicate with the branch device
connected at immediate downstrean-facing port, but updating variables of
SW mst mgr and HW configuration should be conducted anyway. That's because
it's under commit_tail and we need to complete the HW programming.

Changes since v1:
* Remove the set but not use variable 'old_payload' in function
'nv50_msto_prepare'. Catched by kernel test robot <lkp@intel.com>

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230807025639.1612361-3-Wayne.Lin@amd.com

drm/mst: delete unnecessary case in drm_dp_add_payload_part2()

[Why]
There is no need to consider payload->delete case since we won't call
drm_dp_add_payload_part2() to create a payload when we're about to
remove it.

[How]
Delete unnecessary case to simplify the code.

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230807025639.1612361-2-Wayne.Lin@amd.com

drm/dp_mst: Fix NULL deref in get_mst_branch_device_by_guid_helper()

As drm_dp_get_mst_branch_device_by_guid() is called from
drm_dp_get_mst_branch_device_by_guid(), mstb parameter has to be checked,
otherwise NULL dereference may occur in the call to
the memcpy() and cause following:

[12579.365869] BUG: kernel NULL pointer dereference, address: 0000000000000049
[12579.365878] #PF: supervisor read access in kernel mode
[12579.365880] #PF: error_code(0x0000) - not-present page
[12579.365882] PGD 0 P4D 0
[12579.365887] Oops: 0000 [#1] PREEMPT SMP NOPTI
...
[12579.365895] Workqueue: events_long drm_dp_mst_up_req_work
[12579.365899] RIP: 0010:memcmp+0xb/0x29
[12579.365921] Call Trace:
[12579.365927] get_mst_branch_device_by_guid_helper+0x22/0x64
[12579.365930] drm_dp_mst_up_req_work+0x137/0x416
[12579.365933] process_one_work+0x1d0/0x419
[12579.365935] worker_thread+0x11a/0x289
[12579.365938] kthread+0x13e/0x14f
[12579.365941] ? process_one_work+0x419/0x419
[12579.365943] ? kthread_blkcg+0x31/0x31
[12579.365946] ret_from_fork+0x1f/0x30

As get_mst_branch_device_by_guid_helper() is recursive, moving condition
to the first line allow to remove a similar one for step over of NULL elements
inside a loop.

Fixes: 5e93b8208d3c ("drm/dp/mst: move GUID storage from mgr, port to only mst branch")
Cc: <stable@vger.kernel.org> # 4.14+
Signed-off-by: Lukasz Majczak <lma@semihalf.com>
Reviewed-by: Radoslaw Biernacki <rad@chromium.org>
Signed-off-by: Manasi Navare <navaremanasi@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230922063410.23626-1-lma@semihalf.com

drm: use mgr->dev in drm_dbg_kms in drm_dp_add_payload_part2

I've been experiencing some intermittent crashes down in the display
driver code. The symptoms are ususally a line like this in dmesg:

amdgpu 0000:30:00.0: [drm] Failed to create MST payload for port 000000006d3a3885: -5

...followed by an Oops due to a NULL pointer dereference.

Switch to using mgr->dev instead of state->dev since "state" can be
NULL in some cases.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2184855
Suggested-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230419112447.18471-1-jlayton@kernel.org

drm/dp_mst: Clear MSG_RDY flag before sending new message

[Why]
The sequence for collecting down_reply from source perspective should
be:

Request_n->repeat (get partial reply of Request_n->clear message ready
flag to ack DPRX that the message is received) till all partial
replies for Request_n are received->new Request_n+1.

Now there is chance that drm_dp_mst_hpd_irq() will fire new down
request in the tx queue when the down reply is incomplete. Source is
restricted to generate interveleaved message transactions so we should
avoid it.

Also, while assembling partial reply packets, reading out DPCD DOWN_REP
Sideband MSG buffer + clearing DOWN_REP_MSG_RDY flag should be
wrapped up as a complete operation for reading out a reply packet.
Kicking off a new request before clearing DOWN_REP_MSG_RDY flag might
be risky. e.g. If the reply of the new request has overwritten the
DPRX DOWN_REP Sideband MSG buffer before source writing one to clear
DOWN_REP_MSG_RDY flag, source then unintentionally flushes the reply
for the new request. Should handle the up request in the same way.

[How]
Separete drm_dp_mst_hpd_irq() into 2 steps. After acking the MST IRQ
event, driver calls drm_dp_mst_hpd_irq_send_new_request() and might
trigger drm_dp_mst_kick_tx() only when there is no on going message
transaction.

Changes since v1:
* Reworked on review comments received
-> Adjust the fix to let driver explicitly kick off new down request
when mst irq event is handled and acked
-> Adjust the commit message

Changes since v2:
* Adjust the commit message
* Adjust the naming of the divided 2 functions and add a new input
parameter "ack".
* Adjust code flow as per review comments.

Changes since v3:
* Update the function description of drm_dp_mst_hpd_irq_handle_event

Changes since v4:
* Change ack of drm_dp_mst_hpd_irq_handle_event() to be an array align
the size of esi[]

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/display/dp_mst: convert to struct drm_edid

Convert the topology manager to use struct drm_edid, add
drm_dp_mst_edid_read() that returns drm_edid, and rewrite the old
drm_dp_mst_get_edid() to use it.

Note that the old drm_get_edid() ended up calling
drm_connector_update_edid_property(). This responsibility is now
deferred to drivers, which all do it anyway after calling
drm_dp_mst_edid_read() or drm_dp_mst_get_edid().

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/9c32e5c241934093fc4144eed4c01155e1f03af1.1685437501.git.jani.nikula@intel.com

drm/display/dp_mst: drop has_audio from struct drm_dp_mst_port

Caching the has_audio in struct drm_dp_mst_port seems odd, and oddly
placed. Defer audio handling to drivers, and use the info from the
connector display info. i915 was the only one using it anyway.

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7d9eefdf150870479c5797f027d4c2b0a19ff583.1685437500.git.jani.nikula@intel.com

drm/display/dp_mst: Replace all non-returning strlcpy with strscpy

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230522155124.2336545-1-azeemshaikh38@gmail.com

drm/display/dp_mst: Add drm_atomic_get_old_mst_topology_state()

Add a function to get the old MST topology state, required by a
follow-up i915 patch.

While at it clarify the code comment of
drm_atomic_get_new_mst_topology_state() and add _new prefix
to the new state pointer to remind about its difference from the old
state.

v2: Use old_/new_ prefixes for the state pointers. (Ville)

Cc: Lyude Paul <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org # 6.1
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Lyude Paul <lyude@redhat.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230206114856.2665066-3-imre.deak@intel.com

drm/display/dp_mst: Handle old/new payload states in drm_dp_remove_payload()

Atm, drm_dp_remove_payload() uses the same payload state to both get the
vc_start_slot required for the payload removal DPCD message and to
deduct time_slots from vc_start_slot of all payloads after the one being
removed.

The above isn't always correct, as vc_start_slot must be the up-to-date
version contained in the new payload state, but time_slots must be the
one used when the payload was previously added, contained in the old
payload state. The new payload's time_slots can change vs. the old one
if the current atomic commit changes the corresponding mode.

This patch let's drivers pass the old and new payload states to
drm_dp_remove_payload(), but keeps these the same for now in all drivers
not to change the behavior. A follow-up i915 patch will pass in that
driver the correct old and new states to the function.

Cc: Lyude Paul <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: stable@vger.kernel.org # 6.1
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Lyude Paul <lyude@redhat.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230206114856.2665066-2-imre.deak@intel.com

drm/display/dp_mst: Correct the kref of port.

[why & how]
We still need to refer to port while removing payload at commit_tail.
we should keep the kref till then to release.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2171
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Fixes: 4d07b0bc4034 ("drm/display/dp_mst: Move all payload info into the atomic state")
Cc: stable@vger.kernel.org # 6.1
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Tested-by: Didier Raboud <odyx@debian.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/display/dp_mst: Fix payload addition on a disconnected sink

If an MST stream is enabled on a disconnected sink, the payload for the
stream is not created and the MST manager's payload count/next start VC
slot is not updated. Since the payload's start VC slot may still contain
a valid value (!= -1) the subsequent disabling of such a stream could
cause an incorrect decrease of the payload count/next start VC slot in
drm_dp_remove_payload() and hence later payload additions will fail.

Fix the above by marking the payload as invalid in the above case, so
that it's skipped during payload removal. While at it add a debug print
for this case.

Cc: Lyude Paul <lyude@redhat.com>
Cc: <stable@vger.kernel.org> # v6.1+
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221214184258.2869417-3-imre.deak@intel.com

drm/display/dp_mst: Fix down message handling after a packet reception error

After an error during receiving a packet for a multi-packet DP MST
sideband message, the state tracking which packets have been received
already is not reset. This prevents the reception of subsequent down
messages (due to the pending message not yet completed with an
end-of-message-transfer packet).

Fix the above by resetting the reception state after a packet error.

Cc: Lyude Paul <lyude@redhat.com>
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221214184258.2869417-2-imre.deak@intel.com

drm/display/dp_mst: Fix down/up message handling after sink disconnect

If the sink gets disconnected during receiving a multi-packet DP MST AUX
down-reply/up-request sideband message, the state keeping track of which
packets have been received already is not reset. This results in a failed
sanity check for the subsequent message packet received after a sink is
reconnected (due to the pending message not yet completed with an
end-of-message-transfer packet), indicated by the

"sideband msg set header failed"

error.

Fix the above by resetting the up/down message reception state after a
disconnect event.

Cc: Lyude Paul <lyude@redhat.com>
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221214184258.2869417-1-imre.deak@intel.com

drm/display/dp_mst: Correct the kref of port.

[why & how]
We still need to refer to port while removing payload at commit_tail.
we should keep the kref till then to release.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2171
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Fixes: 4d07b0bc4034 ("drm/display/dp_mst: Move all payload info into the atomic state")
Cc: stable@vger.kernel.org # 6.1
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Tested-by: Didier Raboud <odyx@debian.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/display/dp_mst: Fix drm_dp_mst_add_affected_dsc_crtcs() return code

Looks like that we're accidentally dropping a pretty important return code
here. For some reason, we just return -EINVAL if we fail to get the MST
topology state. This is wrong: error codes are important and should never
be squashed without being handled, which here seems to have the potential
to cause a deadlock.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Fixes: 8ec046716ca8 ("drm/dp_mst: Add helper to trigger modeset on affected DSC MST CRTCs")
Cc: <stable@vger.kernel.org> # v5.6+
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/display/dp_mst: Fix drm_dp_mst_add_affected_dsc_crtcs() return code

Looks like that we're accidentally dropping a pretty important return code
here. For some reason, we just return -EINVAL if we fail to get the MST
topology state. This is wrong: error codes are important and should never
be squashed without being handled, which here seems to have the potential
to cause a deadlock.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Fixes: 8ec046716ca8 ("drm/dp_mst: Add helper to trigger modeset on affected DSC MST CRTCs")
Cc: <stable@vger.kernel.org> # v5.6+
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/dp_mst: Avoid deleting payloads for connectors staying enabled

When an MST connector stays enabled during a commit the connector's MST
state needs to be added to the atomic state, but the corresponding MST
payload allocation shouldn't be set for deletion; fix such modesets by
ensuring the above even if the connector was already enabled before the
modeset.

The issue led to the following:
[ 761.992923] i915 0000:00:02.0: drm_WARN_ON(payload->delete)
[ 761.992949] WARNING: CPU: 6 PID: 1401 at drivers/gpu/drm/display/drm_dp_mst_topology.c:4221 drm_dp_atomic_find_time_slots+0x236/0x280 [drm_display_helper]
[ 761.992955] Modules linked in: snd_hda_intel i915 drm_buddy drm_display_helper drm_kms_helper ttm drm snd_hda_codec_hdmi snd_intel_dspcfg snd_hda_codec snd_hwdep snd_hda_core snd_pcm prime_numbers i2c_algo_bit syscopyarea sysfillrect sysimgblt fb_sys_fops x86_pkg_temp_thermal cdc_ether coretemp crct10dif_pclmul usbnet crc32_pclmul mii ghash_clmulni_intel e1000e mei_me ptp i2c_i801 pps_core mei i2c_smbus intel_lpss_pci fuse [last unloaded: drm]
[ 761.992986] CPU: 6 PID: 1401 Comm: testdisplay Tainted: G U 6.0.0-rc4-imre+ #565
[ 761.992989] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR5 RVP, BIOS ADLPFWI1.R00.3135.A00.2203251419 03/25/2022
[ 761.992990] RIP: 0010:drm_dp_atomic_find_time_slots+0x236/0x280 [drm_display_helper]
[ 761.992994] Code: 4c 8b 67 50 4d 85 e4 75 03 4c 8b 27 e8 03 28 4e e1 48 c7 c1 8b 26 2c a0 4c 89 e2 48 c7 c7 a8 26 2c a0 48 89 c6 e8 31 d5 88 e1 <0f> 0b 49 8b 85 d0 00 00 00 4c 89 fa 48 c7 c6 a0 41 2c a0 48 8b 78
[ 761.992995] RSP: 0018:ffffc9000177ba60 EFLAGS: 00010286
[ 761.992998] RAX: 0000000000000000 RBX: ffff88810d2f1540 RCX: 0000000000000000
[ 761.992999] RDX: 0000000000000001 RSI: ffffffff82368a25 RDI: 00000000ffffffff
[ 761.993000] RBP: ffff888142299d80 R08: ffff8884adbfdfe8 R09: 00000000ffefffff
[ 761.993001] R10: ffff8884a6bfe000 R11: ffff8884ac443c30 R12: ffff888102972f90
[ 761.993002] R13: ffff8881163e2cf0 R14: 00000000000003ac R15: ffff88810c501000
[ 761.993003] FS: 00007f81e4c459c0(0000) GS:ffff888496500000(0000) knlGS:0000000000000000
[ 761.993004] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 761.993005] CR2: 0000555dac962a98 CR3: 0000000123a34006 CR4: 0000000000770ee0
[ 761.993006] PKRU: 55555554
[ 761.993007] Call Trace:
[ 761.993009] <TASK>
[ 761.993012] intel_dp_mst_compute_config+0x19a/0x350 [i915]
[ 761.993090] intel_atomic_check+0xf37/0x3180 [i915]
[ 761.993168] drm_atomic_check_only+0x5d3/0xa60 [drm]
[ 761.993182] drm_atomic_commit+0x56/0xc0 [drm]
[ 761.993192] ? drm_plane_get_damage_clips.cold+0x1c/0x1c [drm]
[ 761.993204] drm_atomic_helper_set_config+0x78/0xc0 [drm_kms_helper]
[ 761.993214] drm_mode_setcrtc+0x1ed/0x750 [drm]
[ 761.993232] ? drm_mode_getcrtc+0x180/0x180 [drm]
[ 761.993241] drm_ioctl_kernel+0xb5/0x150 [drm]
[ 761.993252] drm_ioctl+0x203/0x3d0 [drm]
[ 761.993261] ? drm_mode_getcrtc+0x180/0x180 [drm]
[ 761.993276] __x64_sys_ioctl+0x8a/0xb0
[ 761.993281] do_syscall_64+0x38/0x90
[ 761.993285] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 761.993287] RIP: 0033:0x7f81e551aaff
[ 761.993288] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 77 1f 48 8b 44 24 18 64 48 2b 04 25 28 00
[ 761.993290] RSP: 002b:00007fff4304af10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 761.993292] RAX: ffffffffffffffda RBX: 00007fff4304afa0 RCX: 00007f81e551aaff
[ 761.993293] RDX: 00007fff4304afa0 RSI: 00000000c06864a2 RDI: 0000000000000004
[ 761.993294] RBP: 00000000c06864a2 R08: 0000000000000000 R09: 0000555dac8a9c68
[ 761.993294] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000008c4
[ 761.993295] R13: 0000000000000004 R14: 0000555dac8a9c68 R15: 00007fff4304b098
[ 761.993301] </TASK>

Fixes: 083351e96386 ("drm/display/dp_mst: Fix modeset tracking in drm_dp_atomic_release_vcpi_slots()")
Testcase: igt@testdisplay
Cc: Lyude Paul <lyude@redhat.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220907142542.1681994-1-imre.deak@intel.com

drm/display/dp_mst: Move all payload info into the atomic state

Now that we've finally gotten rid of the non-atomic MST users leftover in
the kernel, we can finally get rid of all of the legacy payload code we
have and move as much as possible into the MST atomic state structs. The
main purpose of this is to make the MST code a lot less confusing to work
on, as there's a lot of duplicated logic that doesn't really need to be
here. As well, this should make introducing features like fallback link
retraining and DSC support far easier.

Since the old payload code was pretty gnarly and there's a Lot of changes
here, I expect this might be a bit difficult to review. So to make things
as easy as possible for reviewers, I'll sum up how both the old and new
code worked here (it took me a while to figure this out too!).

The old MST code basically worked by maintaining two different payload
tables - proposed_vcpis, and payloads. proposed_vcpis would hold the
modified payload we wanted to push to the topology, while payloads held the
payload table that was currently programmed in hardware. Modifications to
proposed_vcpis would be handled through drm_dp_allocate_vcpi(),
drm_dp_mst_deallocate_vcpi(), and drm_dp_mst_reset_vcpi_slots(). Then, they
would be pushed via drm_dp_mst_update_payload_step1() and
drm_dp_mst_update_payload_step2().

Furthermore, it's important to note how adding and removing VC payloads
actually worked with drm_dp_mst_update_payload_step1(). When a VC payload
is removed from the VC table, all VC payloads which come after the removed
VC payload's slots must have their time slots shifted towards the start of
the table. The old code handles this by looping through the entire payload
table and recomputing the start slot for every payload in the topology from
scratch. While very much overkill, this ends up doing the right thing
because we always order the VCPIs for payloads from first to last starting
timeslot.

It's important to also note that drm_dp_mst_update_payload_step2() isn't
actually limited to updating a single payload - the driver can use it to
queue up multiple payload changes so that as many of them can be sent as
possible before waiting for the ACT. This is -technically- not against
spec, but as Wayne Lin has pointed out it's not consistently implemented
correctly in hubs - so it might as well be.

drm_dp_mst_update_payload_step2() is pretty self explanatory and basically
the same between the old and new code, save for the fact we don't have a
second step for deleting payloads anymore -and thus rename it to
drm_dp_mst_add_payload_step2().

The new payload code stores all of the current payload info within the MST
atomic state and computes as much of the state as possible ahead of time.
This has the one exception of the starting timeslots for payloads, which
can't be determined at atomic check time since the starting time slots will
vary depending on what order CRTCs are enabled in the atomic state - which
varies from driver to driver. These are still stored in the atomic MST
state, but are only copied from the old MST state during atomic commit
time. Likewise, this is when new start slots are determined.

Adding/removing payloads now works much more closely to how things are
described in the spec. When we delete a payload, we loop through the
current list of payloads and update the start slots for any payloads whose
time slots came after the payload we just deleted. Determining the starting
time slots for new payloads being added is done by simply keeping track of
where the end of the VC table is in
drm_dp_mst_topology_mgr->next_start_slot. Additionally, it's worth noting
that we no longer have a single update_payload() function. Instead, we now
have drm_dp_mst_add_payload_step1|2() and drm_dp_mst_remove_payload(). As
such, it's now left it up to the driver to figure out when to add or remove
payloads. The driver already knows when it's disabling/enabling CRTCs, so
it also already knows when payloads should be added or removed.

Changes since v1:
* Refactor around all of the completely dead code changes that are
happening in amdgpu for some reason when they really shouldn't even be
there in the first place… :\
* Remove mention of sending one ACT per series of payload updates. As Wayne
Lin pointed out, there are apparently hubs on the market that don't work
correctly with this scheme and require a separate ACT per payload update.
* Fix accidental drop of mst_mgr.lock - Wayne Lin
* Remove mentions of allowing multiple ACT updates per payload change,
mention that this is a result of vendors not consistently supporting this
part of the spec and requiring a unique ACT for each payload change.
* Get rid of reference to drm_dp_mst_port in DC - turns out I just got
myself confused by DC and we don't actually need this.
Changes since v2:
* Get rid of fix for not sending payload deallocations if ddps=0 and just
go back to wayne's fix

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-18-lyude@redhat.com

drm/display/dp_mst: Maintain time slot allocations when deleting payloads

Currently, we set drm_dp_atomic_payload->time_slots to 0 in order to
indicate that we're about to delete a payload in the current atomic state.
Since we're going to be dropping all of the legacy code for handling the
payload table however, we need to be able to ensure that we still keep
track of the current time slot allocations for each payload so we can reuse
this info when asking the root MST hub to delete payloads. We'll also be
using it to recalculate the start slots of each VC.

So, let's keep track of the intent of a payload in drm_dp_atomic_payload by
adding ->delete, which we set whenever we're planning on deleting a payload
during the current atomic commit.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-16-lyude@redhat.com

drm/display/dp_mst: Drop all ports from topology on CSNs before queueing link address work

We want to start cutting down on all of the places that we use port
validation, so that ports may be removed from the topology as quickly as
possible to minimize the number of errors we run into as a result of being
out of sync with the current topology status. This isn't a very typical
scenario and I don't think I've ever even run into it - but since the next
commit is going to make some changes to payload updates depending on their
hotplug status I think it's a probably good idea to take precautions.

Let's do this with CSNs by moving some code around so that we only queue
link address probing work at the end of handling all CSNs - allowing us to
make sure we drop as many topology references as we can beforehand.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-15-lyude@redhat.com

drm/display/dp_mst: Add helpers for serializing SST <-> MST transitions

There's another kind of situation where we could potentially race with
nonblocking modesets and MST, especially if we were to only use the locking
provided by atomic modesetting:

* Display 1 begins as enabled on DP-1 in SST mode
* Display 1 switches to MST mode, exposes one sink in MST mode
* Userspace does non-blocking modeset to disable the SST display
* Userspace does non-blocking modeset to enable the MST display with a
different CRTC, but the SST display hasn't been fully taken down yet
* Execution order between the last two commits isn't guaranteed since they
share no drm resources

We can fix this however, by ensuring that we always pull in the atomic
topology state whenever a connector capable of driving an MST display
performs its atomic check - and then tracking CRTC commits happening on the
SST connector in the MST topology state. So, let's add some simple helpers
for doing that and hook them up in various drivers.

v2:
* Use intel_dp_mst_source_support() to check for MST support in i915, fixes
CI failures

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-14-lyude@redhat.com

drm/display/dp_mst: Fix modeset tracking in drm_dp_atomic_release_vcpi_slots()

Currently with the MST helpers we avoid releasing payloads _and_ avoid
pulling in the MST state if there aren't any actual payload changes. While
we want to keep the first step, we need to now make sure that we're always
pulling in the MST state on all modesets that can modify payloads - even if
the resulting payloads in the atomic state are identical to the previous
ones.

This is mainly to make it so that if a CRTC is still assigned to a
connector but is set to DPMS off, the CRTC still holds it's payload
allocation in the atomic state and still appropriately pulls in the MST
state for commit tracking. Otherwise, we'll occasionally forget to update
MST payloads from changes caused by non-atomic DPMS changes. Doing this
also allows us to track bandwidth limitations in a state correctly even
between DPMS changes, so that there's no chance of a simple ->active change
being rejected by the atomic check.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-11-lyude@redhat.com

drm/display/dp_mst: Don't open code modeset checks for releasing time slots

I'm not sure why, but at the time I originally wrote the find/release time
slot helpers I thought we should avoid keeping modeset tracking out of the
MST helpers. In retrospect though there's no actual good reason to do
this, and the logic has ended up being identical across all the drivers
using the helpers. Also, it needs to be fixed anyway so we don't break
things when going atomic-only with MST.

So, let's just move this code into drm_dp_atomic_release_time_slots() and
stop open coding it.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-10-lyude@redhat.com

drm/display/dp_mst: Add nonblocking helpers for DP MST

As Daniel Vetter pointed out, if we only use the atomic modesetting locks
with MST it's technically possible for a driver with non-blocking modesets
to race when it comes to MST displays - as we make the mistake of not doing
our own CRTC commit tracking in the topology_state object.

This could potentially cause problems if something like this happens:

* User starts non-blocking commit to disable CRTC-1 on MST topology 1
* User starts non-blocking commit to enable CRTC-2 on MST topology 1

There's no guarantee here that the commit for disabling CRTC-2 will only
occur after CRTC-1 has finished, since neither commit shares a CRTC - only
the private modesetting object for MST. Keep in mind this likely isn't a
problem for blocking modesets, only non-blocking.

So, begin fixing this by keeping track of which CRTCs on a topology have
changed by keeping track of which CRTCs we release or allocate timeslots
on. As well, add some helpers for:

* Setting up the drm_crtc_commit structs in the ->commit_setup hook
* Waiting for any CRTC dependencies from the previous topology state

v2:
* Use drm_dp_mst_atomic_setup_commit() directly - Jani

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-9-lyude@redhat.com

drm/display/dp_mst: Add helper for finding payloads in atomic MST state

We already open-code this quite often, and will be iterating through
payloads even more once we've moved all of the payload tracking into the
atomic state. So, let's add a helper for doing this.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-8-lyude@redhat.com

drm/display/dp_mst: Fix confusing docs for drm_dp_atomic_release_time_slots()

For some reason we mention returning 0 if "slots have been added back to
drm_dp_mst_topology_state->avail_slots". This is totally misleading,
avail_slots is simply for figuring out the total number of slots available
in total on the topology and has no relation to the current payload
allocations.

So, let's get rid of that comment.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-6-lyude@redhat.com

drm/display/dp_mst: Call them time slots, not VCPI slots

VCPI is only sort of the correct term here, originally the majority of this
code simply referred to timeslots vaguely as "slots" - and since I started
working on it and adding atomic functionality, the name "VCPI slots" has
been used to represent time slots.

Now that we actually have consistent access to the DisplayPort spec thanks
to VESA, I now know this isn't actually the proper term - as the
specification refers to these as time slots.

Since we're trying to make this code as easy to figure out as possible,
let's take this opportunity to correct this nomenclature and call them by
their proper name - timeslots. Likewise, we rename various functions
appropriately, along with replacing references in the kernel documentation
and various debugging messages.

It's important to note that this patch series leaves the legacy MST code
untouched for the most part, which is fine since we'll be removing it soon
anyhow. There should be no functional changes in this series.

v2:
* Add note that Wayne Lin from AMD suggested regarding slots being between
the source DP Tx and the immediate downstream DP Rx

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-5-lyude@redhat.com

drm/display/dp_mst: Rename drm_dp_mst_vcpi_allocation

In retrospect, the name I chose for this originally is confusing, as
there's a lot more info in here then just the VCPI. This really should be
called a payload. Let's make it more obvious that this is meant to be
related to the atomic state and is about payloads by renaming it to
drm_dp_mst_atomic_payload. Also, rename various variables throughout the
code that use atomic payloads.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-4-lyude@redhat.com

drm/dp_mst: add passthrough_aux to struct drm_dp_mst_port

Currently, there is no way to identify if DSC pass-through can be
enabled and what aux DSC pass-through requests ought to be sent to. So,
add a variable to struct drm_dp_mst_port that keeps track of the
aforementioned information.

Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/dp_mst: fix drm_dp_dpcd_read return value checks

drm_dp_dpcd_read returns the number of bytes read. The previous code
would print garbage on DPCD error, and would exit with on error on
success.

Signed-off-by: Simon Ser <contact@emersion.fr>
Fixes: cb897542c6d2 ("drm/dp_mst: Fix W=1 warnings")
Cc: Lyude Paul <lyude@redhat.com>
Cc: Benjamin Gaignard <benjamin.gaignard@st.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/473500/

drm/dp_mst: Get rid of old comment in drm_atomic_get_mst_topology_state docs

We don't actually care about connection_mutex here anymore, so let's get
rid of the comment mentioning it in this function's kdocs.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220602201757.30431-4-lyude@redhat.com

drm/display/dp_mst: Don't validate port refs in drm_dp_check_and_send_link_address()

Drive-by cleanup, we don't need to validate the port references here as we
already previously went through the effort of refactoring things such that
we're guaranteed to be able to access ->mstb and ->port safely from
drm_dp_check_and_send_link_address(), since the only two places in the
codebase that drop an MST reference in such a way that it would remove it
from the topology are both protected under probe_lock.

Thanks for that, past Lyude!

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220602201757.30431-2-lyude@redhat.com

drm: Drop drm_edid.h from drm_crtc.h

drm_crtc.h has no need for drm_edid.h, so don't include it.
Avoids useless rebuilds of the entire universe when
touching drm_edid.h.

Quite a few placs do currently depend on drm_edid.h without
actually including it directly. All of those need to be fixed
up.

v2: Fix up i915 and msm some more
v3: Fix alphabetical ordering (Sam)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220614090245.30283-1-ville.syrjala@linux.intel.com
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>

drm/dp/mst: Read the extended DPCD capabilities during system resume

The WD22TB4 Thunderbolt dock at least will revert its DP_MAX_LINK_RATE
from HBR3 to HBR2 after system suspend/resume if the DP_DP13_DPCD_REV
registers are not read subsequently also as required.

Fix this by reading DP_DP13_DPCD_REV registers as well, matching what is
done during connector detection. While at it also fix up the same call
in drm_dp_mst_dump_topology().

Cc: Lyude Paul <lyude@redhat.com>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5292
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Cc: <stable@vger.kernel.org> # v5.14+
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220614094537.885472-1-imre.deak@intel.com

drm/dp_mst: Lower down debug info level when receive NAK

[Why]
It's reasonable that we receive NAK while doing DP_REMOTE_DPCD_READ.
Downstream device might reply NAK with the reason and source should
react accordingly.

e.g.
1. When downstream device can't handle corresponding message in time,
it then replies NAK as reason been set as DEFER.
2. When multi-function branch-sink device doesn't enumerate virtual
DP peer devices for those multi-function down facing ports. Without
virtual DPCD, branch device might reply NAK with reason as BAD_PARAM
indicating this port can't do aux DPCD read.

It's expected result. Not an error.

[How]
Use drm_dbg_kms() to replace drm_err() when receive NAK.

Changes since v1:
* drm_dp_mst_topology.c file path changed. Folder was rename from
'dp' to 'display'

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[fixed some indenting issues]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220428124944.1683680-1-Wayne.Lin@amd.com

drm: Rename dp/ to display/

Rename dp/ to display/ to account for additional display-related
helpers, such as HDMI. Update all related include statements. No
functional changes.

Various drivers, such as i915 and amdgpu, use similar naming scheme
by putting code for video-output standards into a local display/
directory. The new directory's name is aligned with this convention.

v2:
* update commit message (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-3-tzimmermann@suse.de