From de93ddf88088f7624b589d0ff3af9effb87e8f3b Mon Sep 17 00:00:00 2001 From: Ville Syrjälä Date: Wed, 19 Feb 2025 18:02:39 +0200 Subject: drm/atomic: Filter out redundant DPMS calls MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Video players (eg. mpv) do periodic XResetScreenSaver() calls to keep the screen on while the video playing. The modesetting ddx plumbs these straight through into the kernel as DPMS setproperty ioctls, without any filtering whatsoever. When implemented via atomic these end up as empty commits on the crtc (which will nonetheless take one full frame), which leads to a dropped frame every time XResetScreenSaver() is called. Let's just filter out redundant DPMS property changes in the kernel to avoid this issue. v2: Explain the resulting commits a bit better (Sima) Document the behaviour in uapi docs (Sima) Cc: stable@vger.kernel.org Testcase: igt/kms_flip/flip-vs-dpms-on-nop Reviewed-by: Simona Vetter Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20250219160239.17502-1-ville.syrjala@linux.intel.com --- drivers/gpu/drm/drm_atomic_uapi.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/gpu/drm/drm_atomic_uapi.c') diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index 370dc676e3aa..fd36b8fd54e9 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -956,6 +956,10 @@ int drm_atomic_connector_commit_dpms(struct drm_atomic_state *state, if (mode != DRM_MODE_DPMS_ON) mode = DRM_MODE_DPMS_OFF; + + if (connector->dpms == mode) + goto out; + connector->dpms = mode; crtc = connector->state->crtc; -- cgit