[RFC PATCH v6 0/3] Add support modifiers for drivers whose planes only support linear layout

[Tomohito Esaki]

Some drivers whose planes only support linear layout fb do not support format
modifiers.
These drivers should support modifiers, however the DRM core should handle this
rather than open-coding in every driver.

In this patch series, these drivers expose format modifiers based on the
following suggestion[1].

On Thu, Nov 18, 2021 at 01:02:11PM +0000, Daniel Stone wrote:
> I think the best way forward here is:
>   - add a new mode_config.cannot_support_modifiers flag, and enable
> this in radeon (plus any other drivers in the same boat)
>   - change drm_universal_plane_init() to advertise the LINEAR modifier
> when NULL is passed as the modifier list (including installing a
> default .format_mod_supported hook)
>   - remove the mode_config.allow_fb_modifiers hook and always
> advertise modifier support, unless
> mode_config.cannot_support_modifiers is set


[1] https://patchwork.kernel.org/project/linux-renesas-soc/patch/20190509054518.10781-1-etom@igel.co.jp/#24602575

v6:
* add Reviewed-by and Acked-by
* add a changelog per-patch

v5: https://www.spinics.net/lists/dri-devel/msg330860.html
* rebase to the latest master branch (5.17-rc1+)
	+ "drm/plane: Make format_mod_supported truly optional" patch [2]
  [2] https://patchwork.freedesktop.org/patch/467940/?series=98255&rev=3

* change default_modifiers array from non-static to static
* remove terminator in default_modifiers array
* use ARRAY_SIZE to get the format_modifier_count
* keep a sanity check in plane init func
* modify several kerneldocs

v4: https://www.spinics.net/lists/dri-devel/msg329508.html
* modify documentation for fb_modifiers_not_supported flag in kerneldoc

v3: https://www.spinics.net/lists/dri-devel/msg329102.html
* change the order as follows:
   1. add fb_modifiers_not_supported flag
   2. add default modifiers
   3. remove allow_fb_modifiers flag
* add a conditional disable in amdgpu_dm_plane_init()

v2: https://www.spinics.net/lists/dri-devel/msg328939.html
* rebase to the latest master branch (5.16.0+)
      + "drm/plane: Make format_mod_supported truly optional" patch [2]

v1: https://www.spinics.net/lists/dri-devel/msg327352.html
* The initial patch set

Tomohito Esaki (3):
  drm: introduce fb_modifiers_not_supported flag in mode_config
  drm: add support modifiers for drivers whose planes only support
    linear layout
  drm: remove allow_fb_modifiers

 drivers/gpu/drm/amd/amdgpu/amdgpu_display.c   |  6 ++---
 drivers/gpu/drm/amd/amdgpu/dce_v10_0.c        |  2 ++
 drivers/gpu/drm/amd/amdgpu/dce_v11_0.c        |  2 ++
 drivers/gpu/drm/amd/amdgpu/dce_v6_0.c         |  1 +
 drivers/gpu/drm/amd/amdgpu/dce_v8_0.c         |  2 ++
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  3 +++
 drivers/gpu/drm/drm_framebuffer.c             |  6 ++---
 drivers/gpu/drm/drm_ioctl.c                   |  2 +-
 drivers/gpu/drm/drm_plane.c                   | 23 +++++++++++--------
 drivers/gpu/drm/nouveau/nouveau_display.c     |  6 +++--
 drivers/gpu/drm/radeon/radeon_display.c       |  2 ++
 .../gpu/drm/selftests/test-drm_framebuffer.c  |  1 -
 include/drm/drm_mode_config.h                 | 18 +++++----------
 include/drm/drm_plane.h                       |  3 +++
 14 files changed, 45 insertions(+), 32 deletions(-)

-- 
2.25.1