diff options
| author | Michel Dänzer <michel.daenzer@amd.com> | 2013-06-12 11:58:44 +0200 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2013-08-08 09:50:25 +1000 |
| commit | e91abf80a0998f326107874c88d549f94839f13c (patch) | |
| tree | 743b587fb344dbb60de8639d71fcabe3054ced60 | |
| parent | 16d5b27250f1fab9fa1adf7b98a92e78d11cb9e2 (diff) | |
| download | linux-e91abf80a0998f326107874c88d549f94839f13c.tar.bz2 | |
drm: Don't pass negative delta to ktime_sub_ns()
It takes an unsigned value. This happens not to blow up on 64-bit
architectures, but it does on 32-bit, causing
drm_calc_vbltimestamp_from_scanoutpos() to calculate totally bogus
timestamps for vblank events. Which in turn causes e.g. gnome-shell to
hang after a DPMS off cycle with current xf86-video-ati Git.
[airlied: regression introduced in drm: use monotonic time in drm_calc_vbltimestamp_from_scanoutpos]
Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59339
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59836
Tested-by: shui yangwei <yangweix.shui@intel.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
| -rw-r--r-- | drivers/gpu/drm/drm_irq.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 8bcce7866d36..f92da0a32f0d 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -708,7 +708,10 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, /* Subtract time delta from raw timestamp to get final * vblank_time timestamp for end of vblank. */ - etime = ktime_sub_ns(etime, delta_ns); + if (delta_ns < 0) + etime = ktime_add_ns(etime, -delta_ns); + else + etime = ktime_sub_ns(etime, delta_ns); *vblank_time = ktime_to_timeval(etime); DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n", |