From: Simon Ser contact@emersion.fr
commit 1ca67aba8d11c2849d395013e1fdce02918d5657 upstream.
Up until now, amdgpu was silently degrading to vsync when user-space requested an async flip but the hardware didn't support it.
The hardware doesn't support immediate flips when the update changes the FB pitch, the DCC state, the rotation, enables or disables CRTCs or planes, etc. This is reflected in the dm_crtc_state.update_type field: UPDATE_TYPE_FAST means that immediate flip is supported.
Silently degrading async flips to vsync is not the expected behavior from a uAPI point-of-view. Xorg expects async flips to fail if unsupported, to be able to fall back to a blit. i915 already behaves this way.
This patch aligns amdgpu with uAPI expectations and returns a failure when an async flip is not possible.
Signed-off-by: Simon Ser contact@emersion.fr Reviewed-by: André Almeida andrealmeid@igalia.com Reviewed-by: Alex Deucher alexander.deucher@amd.com Reviewed-by: Harry Wentland harry.wentland@amd.com Signed-off-by: André Almeida andrealmeid@igalia.com Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 8 ++++++++ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c | 12 ++++++++++++ 2 files changed, 20 insertions(+)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -8055,7 +8055,15 @@ static void amdgpu_dm_commit_planes(stru * Only allow immediate flips for fast updates that don't * change memory domain, FB pitch, DCC state, rotation or * mirroring. + * + * dm_crtc_helper_atomic_check() only accepts async flips with + * fast updates. */ + if (crtc->state->async_flip && + acrtc_state->update_type != UPDATE_TYPE_FAST) + drm_warn_once(state->dev, + "[PLANE:%d:%s] async flip with non-fast update\n", + plane->base.id, plane->name); bundle->flip_addrs[planes_count].flip_immediate = crtc->state->async_flip && acrtc_state->update_type == UPDATE_TYPE_FAST && --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c @@ -398,6 +398,18 @@ static int dm_crtc_helper_atomic_check(s return -EINVAL; }
+ /* + * Only allow async flips for fast updates that don't change the FB + * pitch, the DCC state, rotation, etc. + */ + if (crtc_state->async_flip && + dm_crtc_state->update_type != UPDATE_TYPE_FAST) { + drm_dbg_atomic(crtc->dev, + "[CRTC:%d:%s] async flips are only supported for fast updates\n", + crtc->base.id, crtc->name); + return -EINVAL; + } + /* In some use cases, like reset, no stream is attached */ if (!dm_crtc_state->stream) return 0;