drm/vkms: drop "Rotation" TODO

Now that VKMS supports all values of rotation and reflection, drop the
"Rotation" task from the TODO list.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230418130525.128733-7-mcanal@igalia.com

drm/vkms: drop full alpha blending TODO

Now that VKMS supports full alpha blending on all planes, drop the
"ARGB format on primary plane" and "Full alpha blending on all planes"
tasks from the TODO list.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Arthur Grillo <arthurgrillo@riseup.net>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230420232228.273340-2-mcanal@igalia.com

drm: vkms: Supports to the case where primary plane doesn't match the CRTC

We will remove the current assumption that the primary plane has the
same size and position as CRTC and that the primary plane is the
bottom-most in zpos order, or is even enabled. At least as far
as the blending machinery is concerned.

For that we will add CRTC dimension information to `vkms_crtc_state`
and add a opaque black backgound color.

Because now we need to fill the background, we had a loss in
performance with this change. Results running the IGT[1] test
`igt@kms_cursor_crc@pipe-a-cursor-512x512-onscreen` ten times:

| Frametime |
|:--------------------------------------------:|
| Implementation | Previous | This commit |
|:---------------:|:---------:|:--------------:|
| frametime range | 5~18 ms | 10~22 ms |
| Average | 8.47 ms | 12.32 ms |

[1] IGT commit id: bc3f6833a12221a46659535dac06ebb312490eb4

V6: Improve the commit description (Pekka Paalanen).
Update some comments (Pekka Paalanen).
Remove some fields from `vkms_crtc_state` and move where
some variables are set (Pekka Paalanen).

Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905190811.25024-8-igormtorrente@gmail.com

drm: vkms: Refactor the plane composer to accept new formats

Currently the blend function only accepts XRGB_8888 and ARGB_8888
as a color input.

This patch refactors all the functions related to the plane composition
to overcome this limitation.

The pixels blend is done using the new internal format. And new handlers
are being added to convert a specific format to/from this internal format.

So the blend operation depends on these handlers to convert to this common
format. The blended result, if necessary, is converted to the writeback
buffer format.

This patch introduces three major differences to the blend function.
1 - All the planes are blended at once.
2 - The blend calculus is done as per line instead of per pixel.
3 - It is responsible to calculates the CRC and writing the writeback
buffer(if necessary).

These changes allow us to allocate way less memory in the intermediate
buffer to compute these operations. Because now we don't need to
have the entire intermediate image lines at once, just one line is
enough.

| Memory consumption (output dimensions) |
|:--------------------------------------:|
| Current | This patch |
|:------------------:|:-----------------:|
| Width * Heigth | 2 * Width |

Beyond memory, we also have a minor performance benefit from all
these changes. Results running the IGT[1] test
`igt@kms_cursor_crc@pipe-a-cursor-512x512-onscreen` ten times:

| Frametime |
|:------------------------------------------:|
| Implementation | Current | This commit |
|:---------------:|:---------:|:------------:|
| frametime range | 9~22 ms | 5~17 ms |
| Average | 11.4 ms | 7.8 ms |

[1] IGT commit id: bc3f6833a12221a46659535dac06ebb312490eb4

V2: Improves the performance drastically, by performing the operations
per-line and not per-pixel(Pekka Paalanen).
Minor improvements(Pekka Paalanen).
V3: Changes the code to blend the planes all at once. This improves
performance, memory consumption, and removes much of the weirdness
of the V2(Pekka Paalanen and me).
Minor improvements(Pekka Paalanen and me).
V4: Rebase the code and adapt it to the new NUM_OVERLAY_PLANES constant.
V5: Minor checkpatch fixes and the removal of TO-DO item(Melissa Wen).
Several security/robustness improvents(Pekka Paalanen).
Removes check_planes_x_bounds function and allows partial
partly off-screen(Pekka Paalanen).
V6: Fix a mismatch of some variable sizes (Pekka Paalanen).
Several minor improvements (Pekka Paalanen).

Reviewed-by: Melissa Wen <mwen@igalia.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905190811.25024-7-igormtorrente@gmail.com

drm: vkms: Alloc the compose frame using vzalloc

Currently, the memory to the composition frame is being allocated using
the kzmalloc. This comes with the limitation of maximum size of one
page size(which in the x86_64 is 4Kb and 4MB for default and hugepage
respectively).

Somes test of igt (e.g. kms_plane@pixel-format) uses more than 4MB when
testing some pixel formats like ARGB16161616 and the following error were
showing up when running kms_plane@plane-panning-bottom-right*:

[drm:vkms_composer_worker [vkms]] *ERROR* Cannot allocate memory for
output frame.

This problem is addessed by allocating the memory using kvzalloc that
circunvents this limitation.

V5: Improve the commit message and drop the debugging issues in VKMS
TO-DO(Melissa Wen).

Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220404204515.42144-2-igormtorrente@gmail.com

drm/vkms: drop "Multiple overlay planes" TODO

Remove the task from the TODO list.

Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220107182809.141003-3-jose.exposito89@gmail.com

drm/vkms: update the current status of todo list

Update:
- debugging issues on igt testcases
- plane composition features: add primary plane improvements
- suggestions of good tasks to start working on vkms

Drop:
- syzkaller bug report:
what triggered the warning was replaced by shmem functions at
https://patchwork.freedesktop.org/patch/394614/
- overlay plane: this feature was added by
https://patchwork.freedesktop.org/patch/430941/

Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210626092655.ghmmt2yux5klrne7@smtp.gmail.com

drm/vkms: Add information about module options

Update vkms documentation to contain usage of `modinfo`
command and steps to load vkms with module options enabled.

Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Reviewed-by: Melissa Wen <melissa.srw@gmail.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4fbc6459377c1dcbe8e6648718453d5693f6451c.1610391685.git.sylphrenadin@gmail.com

drm/vkms: Add setup and testing information

Update the vkms documentation to contain steps to:

- setup the vkms driver
- run tests using igt

Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201209190453.c6kp5winikr55n3i@adolin

drm/vkms: update todo

Drop issues already resolved in vkms:

- CRC API Improvements to [1] add igt test to check extreme alpha values
and [2] alpha blending;
- [3] prime buffer sharing;
- [4] writeback support;

On the other hand, we also found or thought about other improvements since
the last update of this document:

- better support for IGT tests
- improvements to writeback support
- syzbot report

Finally, we reorder items by the assumed complexity.

[1] https://patchwork.freedesktop.org/series/55944/
[2] https://patchwork.freedesktop.org/series/80823/
[3] https://patchwork.freedesktop.org/series/63212/
[4] https://patchwork.freedesktop.org/series/81177/

v2:
- Link to syzbot dashboard

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>

Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201006223006.gu55pjtuaigkh6il@smtp.gmail.com

drm/doc: Remove solved "VBlank issues"

Remove the list of broken tests on VKMS solved by patchset
https://patchwork.freedesktop.org/series/55994/

Signed-off-by: Shayenne Moura <shayenneluzmoura@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190206193157.3b53ipdxtcqc4hv4@smtp.gmail.com

drm/vkms: Extend todo

Typed up all the items Rodrigo capture at the vkms workshop at
xdc2018:

https://etherpad.net/p/vkms_todo

v2: Review from Rodrigo.
- Add eBPF for atomic check, I forgot it.
- Improve spelling.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181003132103.29309-1-daniel.vetter@ffwll.ch

drm/vkms: Add kerneldoc entry

Add an initial kerneldoc entry for vkms with a todo list.

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
[danvet: Keep the todo.rst entry to point at the vkms docs instead.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180907174136.GA2648@haneenDRM