[PATCH] drm/amdgpu: Ensure that the modifier requested is supported by plane.

[Michel Dänzer]

On 2021-03-23 4:32 p.m., Mark Yacoub wrote:
> On Tue, Mar 23, 2021 at 11:02 AM Alex Deucher <alexdeucher at gmail.com> wrote:
>>
>> On Wed, Mar 10, 2021 at 11:15 AM Mark Yacoub <markyacoub at chromium.org> wrote:
>>>
>>> From: Mark Yacoub <markyacoub at google.com>
>>>
>>> On initializing the framebuffer, call drm_any_plane_has_format to do a
>>> check if the modifier is supported. drm_any_plane_has_format calls
>>> dm_plane_format_mod_supported which is extended to validate that the
>>> modifier is on the list of the plane's supported modifiers.
>>>
>>> The bug was caught using igt-gpu-tools test: kms_addfb_basic.addfb25-bad-modifier
>>>
>>> Tested on ChromeOS Zork by turning on the display, running an overlay
>>> test, and running a YT video.
>>>
>>> Cc: Alex Deucher <alexander.deucher at amd.com>
>>> Cc: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
>>> Signed-off-by: default avatarMark Yacoub <markyacoub at chromium.org>
>>
>> I'm not an expert with modifiers yet.  Will this break chips which
>> don't currently support modifiers?
> No it shouldn't. When you don't support modifiers yet, your will
> default to Linear Modifier (DRM_FORMAT_MOD_LINEAR),
> [...]
No modifier support does not imply linear. It's generally signalled via DRM_FORMAT_MOD_INVALID, which roughly means "tiling is determined by driver specific mechanisms".


-- 
Earthling Michel Dänzer               |               https://redhat.com
Libre software enthusiast             |             Mesa and X developer