[PATCH 0/3] drm/amd/display: fixes for kernel crashes since cursor overlay mode

[Melissa Wen]

On 19/12/2024 18:23, Rodrigo Siqueira Jordao wrote:
>
>
> On 12/17/24 1:45 PM, Melissa Wen wrote:
>> Hi,
>>
>> Some issues have been found by Cosmic users of AMD display since the
>> introduction of cursor overlay mode: page fault and divide errors
>> causing interface freezes. Both are 100% reproducible and affects
>> multiple HW versions.
>>
>> Patch 1 addresses the page fault error by resolving the definition
>> mismatch around the number of surfaces supported by the hw, where two
>> different values (MAX_SURFACES and MAX_SURFACE_NUM) would be taken
>> through the DC surface updates flow. The regular flow take MAX_SURFACES
>> == 3 into account and commit_minimal_transition_state uses
>> MAX_SURFACE_NUM == 6. I noticed that Leo Li has proposed this change in
>> a previous discussion [1], so I added a Suggested-by tag.
>>
>> Patch 2 expands the maximum number of surfaces to four, since it's
>> supported by the hw. Also, this amount accomodates current needs,
>> avoiding `dc_state_add_plane` complaints of not enough resource. Note
>> that it somehow reverts the change proposed by [2].
>>
>> Related AMD issues:
>> - https://gitlab.freedesktop.org/drm/amd/-/issues/3693
>> - https://gitlab.freedesktop.org/drm/amd/-/issues/3594
>>
>> Patch 3 fixes a kernel oops due to division by zero error by checking if
>> the destination scale size is zero, avoiding calculation and just
>> setting the out-scale size to zero, similar to what is  done by
>> drm_calc_scale(). Even though the missing check in dm_get_plane_scale()
>> wasn't introduced by cursor overlay mode, AFAIU the cursor mode
>> assessment happens before plane state checks, so
>> amdgpu_dm_plane_helper_check_state() can't prevent
>> dm_crtc_get_cursor_mode() taking an invisible plane into account.
>>
>> Related AMD issue:
>> - https://gitlab.freedesktop.org/drm/amd/-/issues/3729
>>
>> Other previous discussions can be found at:
>> - 
>> https://lore.kernel.org/amd-gfx/20241114143741.627128-1-zaeem.mohamed@amd.com/
>> - 
>> https://lore.kernel.org/amd-gfx/20240925154324.348774-1-mwen@igalia.com/
>>
>> Thanks in advance for any feedback.
>>
>> Melissa
>>
>> [1] 
>> https://lore.kernel.org/amd-gfx/20241025193727.765195-2-zaeem.mohamed@amd.com/
>> [2] https://gitlab.freedesktop.org/agd5f/linux/-/commit/3cfd03b79425c
>>
>> Melissa Wen (3):
>>    drm/amd/display: fix page fault due to max surface definition 
>> mismatch
>>    drm/amd/display: increase MAX_SURFACES to the value supported by hw
>>    drm/amd/display: fix divide error in DM plane scale calcs
>>
>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c       | 4 ++--
>>   drivers/gpu/drm/amd/display/dc/core/dc.c                | 2 +-
>>   drivers/gpu/drm/amd/display/dc/core/dc_state.c          | 8 ++++----
>>   drivers/gpu/drm/amd/display/dc/dc.h                     | 4 ++--
>>   drivers/gpu/drm/amd/display/dc/dc_stream.h              | 2 +-
>>   drivers/gpu/drm/amd/display/dc/dc_types.h               | 1 -
>>   drivers/gpu/drm/amd/display/dc/dml2/dml2_mall_phantom.c | 2 +-
>>   7 files changed, 11 insertions(+), 12 deletions(-)
>>
>
> Hi Melissa,
>
> Thanks a lot for your series. I tested it on a couple of hardware 
> devices, and I think everything is alright.
>
> Series is
> Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
>
> and your series was merged into the amd-staging-drm-next.

Hi Siqueira,

Nice! Thanks!

Melissa
>
> Thanks
> Siqueira
>
>