diff options
Diffstat (limited to 'drivers/gpu/drm/drm_atomic.c')
| -rw-r--r-- | drivers/gpu/drm/drm_atomic.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index 2ba729eec451..b2d20eb6c807 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -281,6 +281,10 @@ EXPORT_SYMBOL(__drm_atomic_state_free); * needed. It will also grab the relevant CRTC lock to make sure that the state * is consistent. * + * WARNING: Drivers may only add new CRTC states to a @state if + * drm_atomic_state.allow_modeset is set, or if it's a driver-internal commit + * not created by userspace through an IOCTL call. + * * Returns: * * Either the allocated state or the error code encoded into the pointer. When @@ -1262,10 +1266,15 @@ int drm_atomic_check_only(struct drm_atomic_state *state) struct drm_crtc_state *new_crtc_state; struct drm_connector *conn; struct drm_connector_state *conn_state; + unsigned requested_crtc = 0; + unsigned affected_crtc = 0; int i, ret = 0; DRM_DEBUG_ATOMIC("checking %p\n", state); + for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) + requested_crtc |= drm_crtc_mask(crtc); + for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) { ret = drm_atomic_plane_check(old_plane_state, new_plane_state); if (ret) { @@ -1313,6 +1322,26 @@ int drm_atomic_check_only(struct drm_atomic_state *state) } } + for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) + affected_crtc |= drm_crtc_mask(crtc); + + /* + * For commits that allow modesets drivers can add other CRTCs to the + * atomic commit, e.g. when they need to reallocate global resources. + * This can cause spurious EBUSY, which robs compositors of a very + * effective sanity check for their drawing loop. Therefor only allow + * drivers to add unrelated CRTC states for modeset commits. + * + * FIXME: Should add affected_crtc mask to the ATOMIC IOCTL as an output + * so compositors know what's going on. + */ + if (affected_crtc != requested_crtc) { + DRM_DEBUG_ATOMIC("driver added CRTC to commit: requested 0x%x, affected 0x%0x\n", + requested_crtc, affected_crtc); + WARN(!state->allow_modeset, "adding CRTC not allowed without modesets: requested 0x%x, affected 0x%0x\n", + requested_crtc, affected_crtc); + } + return 0; } EXPORT_SYMBOL(drm_atomic_check_only); |