From: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx> commit bb46a6a9bab134b9d15043ea8fa9d6c276e938b8 upstream. The function dc_update_planes_and_stream handles multiple cases where DC needs to remove and add planes in the commit tail phase. After Linux started to use this function, some of the IGT kms_plane started to fail; one good example to illustrate why the new sequence regressed IGT is the subtest plane-position-hole which has the following diagram as a template: +--------------------+ +-----------------------+ | +-----+ | | +-----+ | | | | | | | +-----+ | | | +--+ | ==> | | | | | | | |__| | | +-|---+ | | | | | +-----+ | | | | | +--------------------+ +-----------------------+ (a) Final image (b) Composed image IGT expects image (a) as the final result of two plane compositions as described in figure (b). After the migration to the new sequence, the last plane order is changed, and DC generates the following image: +---------------------+ | +-----+ | | | | | | | | | | +-----+ | | | +---------------------+ Notice that the generated image by DC is different because the small square that should be composed on top of the primary plane is below the primary plane. For this reason, the CRC will mismatch with the expected value. Since the function dc_add_all_planes_for_stream re-append all the new planes back to the dc_validation_set, this commit ensures that the original sequence is maintained. After this change, all CI tests in all ASICs start to pass again. Reviewed-by: Harry Wentland <Harry.Wentland@xxxxxxx> Acked-by: Qingqing Zhuo <qingqing.zhuo@xxxxxxx> Suggested-by: Melissa Wen <mwen@xxxxxxxxxx> Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx> Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Cc: Mario Limonciello <mario.limonciello@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -351,6 +351,19 @@ static inline bool is_dc_timing_adjust_n return false; } +static inline void reverse_planes_order(struct dc_surface_update *array_of_surface_update, + int planes_count) +{ + int i, j; + struct dc_surface_update surface_updates_temp; + + for (i = 0, j = planes_count - 1; i < j; i++, j--) { + surface_updates_temp = array_of_surface_update[i]; + array_of_surface_update[i] = array_of_surface_update[j]; + array_of_surface_update[j] = surface_updates_temp; + } +} + /** * update_planes_and_stream_adapter() - Send planes to be updated in DC * @@ -367,6 +380,8 @@ static inline bool update_planes_and_str struct dc_stream_update *stream_update, struct dc_surface_update *array_of_surface_update) { + reverse_planes_order(array_of_surface_update, planes_count); + /* * Previous frame finished and HW is ready for optimization. */