[Resending due to temporary mailing list server error on gabe.freedesktop.org - trying again to reach dri-devel and amd-gfx] Hi, This is another attempt to approach page fault error faced by Cosmic users of AMD display hw that exposes two overlay planes. It was first reported as an interface freeze caused by array-index-out-of-bounds, where the number of active planes was greater than the maximum number of surfaces reported. This number of active planes started to be greater with the introduction of cursor overlay mode, so a situation in which one primary, two overlays and one cursor overlay == 4 became possible. After further investigation, I noticed there was a definition mismatch around the number of surfaces supported by the hw, and two different values (MAX_SURFACES and MAX_SURFACE_NUM) would be taken through the DC surface updates flow. Also, the main cause of the interface freeze seems to be a page fault error, where the regular flow take MAX_SURFACES == 3 into account and commit_minimal_transition_state uses MAX_SURFACE_NUM == 6. AFAIU, four is the maximum number of surfaces supported by the hw and this amount accomodates current needs, that's why this proposal is aligned with this number. However, this may not be the right value again according to a commit in the driver branch that states that 6 is "the max surfaces supported asics can have" [1]. Misleading change? Previous discussions can be found at: - https://lore.kernel.org/amd-gfx/20241114143741.627128-1-zaeem.mohamed@xxxxxxx/ - https://lore.kernel.org/amd-gfx/20241025193727.765195-2-zaeem.mohamed@xxxxxxx/ - https://lore.kernel.org/amd-gfx/20240925154324.348774-1-mwen@xxxxxxxxxx/ Reported issues (and more discussions) related to this series are at AMD issue tracker: - https://gitlab.freedesktop.org/drm/amd/-/issues/3693 - https://gitlab.freedesktop.org/drm/amd/-/issues/3594 Please let me know your thoughts. Melissa [1] https://gitlab.freedesktop.org/agd5f/linux/-/commit/3cfd03b79425c Melissa Wen (2): drm/amd/display: fix page fault due to max surface definition mismatch drm/amd/display: increase MAX_SURFACES to the value supported by hw 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 +- 6 files changed, 9 insertions(+), 10 deletions(-) -- 2.45.2
