diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index 14b321580517..6050c80f1dbc 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -508,6 +508,22 @@ static int drm_atomic_crtc_check(struct drm_crtc *crtc, return -EINVAL; } + /* + * Reject event generation for when a CRTC is off and stays off. + * It wouldn't be hard to implement this, but userspace has a track + * record of happily burning through 100% cpu (or worse, crash) when the + * display pipe is suspended. To avoid all that fun just reject updates + * that ask for events since likely that indicates a bug in the + * compositor's drawing loop. This is consistent with the vblank IOCTL + * and legacy page_flip IOCTL which also reject service on a disabled + * pipe. + */ + if (state->event && !state->active && !crtc->state->active) { + DRM_DEBUG_ATOMIC("[CRTC:%d] requesting event but off\n", + crtc->base.id); + return -EINVAL; + } + return 0; } diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 26d258d0618b..738104b68d26 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -2284,6 +2284,15 @@ int drm_atomic_helper_page_flip(struct drm_crtc *crtc, goto fail; drm_atomic_set_fb_for_plane(plane_state, fb); + /* Make sure we don't accidentally do a full modeset. */ + state->allow_modeset = false; + if (!crtc_state->active) { + DRM_DEBUG_ATOMIC("[CRTC:%d] disabled, rejecting legacy flip\n", + crtc->base.id); + ret = -EINVAL; + goto fail; + } + ret = drm_atomic_async_commit(state); if (ret != 0) goto fail; diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index e3c4d486e1af..c65a212db77e 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -551,7 +551,8 @@ struct drm_crtc_funcs { * ->page_flip() operation is already pending the callback should return * -EBUSY. Pageflips on a disabled CRTC (either by setting a NULL mode * or just runtime disabled through DPMS respectively the new atomic - * "ACTIVE" state) should result in an -EINVAL error code. + * "ACTIVE" state) should result in an -EINVAL error code. Note that + * drm_atomic_helper_page_flip() checks this already for atomic drivers. */ int (*page_flip)(struct drm_crtc *crtc, struct drm_framebuffer *fb,