In
commit 99264a61dfcda41d86d0960cf2d4c0fc2758a773
Author: Daniel Vetter <daniel.vetter@xxxxxxxx>
Date: Wed Apr 15 19:34:43 2015 +0200
drm/vblank: Fixup and document timestamp update/read barriers
I've switched vblank->count from atomic_t to unsigned long and
accidentally created an integer comparison bug in
drm_vblank_count_and_time since vblanke->count might overflow the u32
local copy and hence the retry loop never succeed.
Fix this by consistently using u32.
Cc: Michel Dänzer <michel@xxxxxxxxxxx>
Reported-by: Michel Dänzer <michel@xxxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
drivers/gpu/drm/drm_irq.c | 2 +-
include/drm/drmP.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index a7311c6e6f30..a2cfd2cc8c39 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -75,7 +75,7 @@ module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600)
module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
static void store_vblank(struct drm_device *dev, int crtc,
- unsigned vblank_count_inc,
+ u32 vblank_count_inc,
struct timeval *t_vblank)
{
struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index fdf8a501cb44..38e0e77d7277 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -691,7 +691,7 @@ struct drm_vblank_crtc {
struct timer_list disable_timer; /* delayed disable timer */
/* vblank counter, protected by dev->vblank_time_lock for writes */
- unsigned long count;
+ u32 count;
/* vblank timestamps, protected by dev->vblank_time_lock for writes */
struct timeval time[DRM_VBLANKTIME_RBSIZE];
--
2.5.0
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