History log of /linux-master/include/drm/display/drm_dp_mst_helper.h
Revision Date Author Comments
# 191dc439 16-Nov-2023 Imre Deak <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


# 1cd0a5ea 23-Oct-2023 Imre Deak <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


# 9dcf67de 23-Oct-2023 Imre Deak <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


# 7707dd60 23-Oct-2023 Ville Syrjälä <ville.syrjala@linux.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


# 5aa1dfcd 06-Aug-2023 Wayne Lin <Wayne.Lin@amd.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


# 72f1de49 17-Apr-2023 Wayne Lin <Wayne.Lin@amd.com>

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>


# c1c9042b 29-May-2023 Jani Nikula <jani.nikula@intel.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


# 3d35ddfb 29-May-2023 Jani Nikula <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


# 9ffdb67a 06-Feb-2023 Imre Deak <imre.deak@intel.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


# e761cc20 06-Feb-2023 Imre Deak <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


# 4d07b0bc 17-Aug-2022 Lyude Paul <lyude@redhat.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


# 6366fc70 17-Aug-2022 Lyude Paul <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


# a76eb429 17-Aug-2022 Lyude Paul <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


# a5c2c0d1 17-Aug-2022 Lyude Paul <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


# 0bee2ae2 17-Aug-2022 Lyude Paul <lyude@redhat.com>

drm/display/dp_mst: Add some missing kdocs for atomic MST structs

Since we're about to start adding some stuff here, we may as well fill in
any missing documentation that we forgot to write.

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/20220817193847.557945-7-lyude@redhat.com


# df78f7f6 17-Aug-2022 Lyude Paul <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


# 48b6b372 17-Aug-2022 Lyude Paul <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


# 34f66763 04-Aug-2022 Hamza Mahfooz <hamza.mahfooz@amd.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>


# da68386d 21-Apr-2022 Thomas Zimmermann <tzimmermann@suse.de>

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