atomic_flush will be called for each CRTC even if they aren't enabled.
The whole code we have there will thus run without a properly affected channel, which can then result in all sorts of weird behaviour.
Fortunately, the DRM_PLANE_COMMIT_ACTIVE_ONLY flag will skip the CRTC atomic_begin and atomic_flush, and the planes atomic_update, if they aren't enabled.
Our plane atomic_update is a nop, and atomic_begin will copy the current HVS channel to the vc4_crtc structure for the interrupt handler to consume, but the handler won't run if the CRTC is disabled. So in the end, it will only skip our CRTC atomic_flush, which is what we want.
Signed-off-by: Maxime Ripard maxime@cerno.tech --- drivers/gpu/drm/vc4/vc4_kms.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c index 992d6a240002..928657c736b7 100644 --- a/drivers/gpu/drm/vc4/vc4_kms.c +++ b/drivers/gpu/drm/vc4/vc4_kms.c @@ -401,7 +401,8 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state) else vc4_hvs_pv_muxing_commit(vc4, state);
- drm_atomic_helper_commit_planes(dev, state, 0); + drm_atomic_helper_commit_planes(dev, state, + DRM_PLANE_COMMIT_ACTIVE_ONLY);
drm_atomic_helper_commit_modeset_enables(dev, state);