summaryrefslogtreecommitdiffstats
path: root/drivers/gpu
diff options
context:
space:
mode:
authorDaniel Vetter <daniel.vetter@ffwll.ch>2015-12-08 09:49:20 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-01-05 10:07:51 +0100
commit4cba68507cf58db99752cf79198beb4a85a9f8ce (patch)
treece0e53f48983a7414baedc51df01a284908fe7e6 /drivers/gpu
parent4cd9fa529d77dde8f760adb3d934dfac6e169b1e (diff)
downloadop-kernel-dev-4cba68507cf58db99752cf79198beb4a85a9f8ce.zip
op-kernel-dev-4cba68507cf58db99752cf79198beb4a85a9f8ce.tar.gz
drm/atomic-helper: Reject legacy flips on a disabled pipe
We want this for consistency with existing page_flip semantics. Since this spurred quite a discussion on IRC also document why we reject event generation when the pipe is off: It's not that it's hard to implement, but userspace has a track recording which proves that it's way too easy to accidentally abuse and cause havoc. We want to make sure userspace doesn't get away with that. v2: Somehow thought we do reject events already, but that code only existed in my imagination ... Also suggestions from Thierry. Cc: Daniel Stone <daniels@collabora.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Thierry Reding <thierry.reding@gmail.com> Reviewed-by: Daniel Stone <daniels@collabora.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1449564561-3896-4-git-send-email-daniel.vetter@ffwll.ch
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/drm_atomic.c16
-rw-r--r--drivers/gpu/drm/drm_atomic_helper.c9
2 files changed, 25 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 14b3215..6050c80f 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 26d258d..738104b 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2284,6 +2284,15 @@ retry:
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;
OpenPOWER on IntegriCloud