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@xxxxxxx/ - https://lore.kernel.org/amd-gfx/20240925154324.348774-1-mwen@xxxxxxxxxx/ Thanks in advance for any feedback. Melissa [1] https://lore.kernel.org/amd-gfx/20241025193727.765195-2-zaeem.mohamed@xxxxxxx/ [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(-) -- 2.45.2
