drm/vblank: Use u32 consistently for vblank counters

In

commit 99264a61dfcda41d86d0960cf2d4c0fc2758a773
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
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@daenzer.net>
Reported-by: Michel Dänzer <michel@daenzer.net>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index f9cc68f..b50fa0a 100644 (file)
--- 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 48db6a5..5aa5197 100644 (file)
--- 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];