From c1e18c44dc7f70a411d94f24f437a320b327887c Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Wed, 21 Jun 2023 17:24:59 -0300 Subject: drm/amd/display: only accept async flips for fast updates MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: André Almeida Reviewed-by: Alex Deucher Reviewed-by: Harry Wentland Signed-off-by: André Almeida Signed-off-by: Hamza Mahfooz Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c') diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c index 440fc0869a34..30d4c6fd95f5 100644 --- 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(struct drm_crtc *crtc, 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; -- cgit v1.2.3