On Wed, 2013-06-12 at 11:58 +0200, Michel Dänzer wrote:
From: Michel Dänzer michel.daenzer@amd.com
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.
Cc: stable@vger.kernel.org Signed-off-by: Michel Dänzer michel.daenzer@amd.com
Yes, I introduced this regression in:
drm: use monotonic time in drm_calc_vbltimestamp_from_scanoutpos
The fix seems to be ok, perhaps you should also mention the regressing commit in the commit message.
Reviewed-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/drm_irq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index a6a8643..39665f8 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",