diff options
| author | Matthew Auld <matthew.auld@intel.com> | 2016-05-10 15:21:28 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-05-24 23:21:56 +0200 |
| commit | d4055a9b207966ab4058550d818532b979d8bf78 (patch) | |
| tree | 6e97fa8a8c4fe75fccc929bf223a23c2c727e595 /include/drm/drmP.h | |
| parent | b80d3942329dcd43580adc3f7c0a098515b5feec (diff) | |
| download | linux-d4055a9b207966ab4058550d818532b979d8bf78.tar.bz2 | |
drm: use seqlock for vblank time/count
This patch aims to replace the roll-your-own seqlock implementation with
full-blown seqlock'. We also remove the timestamp ring-buffer in favour
of single timestamp/count pair protected by a seqlock. In turn this
means we can now increment the vblank freely without the need for
clamping.
v2:
- reduce the scope of the seqlock, keeping vblank_time_lock
- make the seqlock per vblank_crtc, so multiple readers aren't blocked by
the writer
Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1462890088-18194-1-git-send-email-matthew.auld@intel.com
Diffstat (limited to 'include/drm/drmP.h')
| -rw-r--r-- | include/drm/drmP.h | 14 |
1 files changed, 5 insertions, 9 deletions
diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 84f1a8eefbdb..af8b71b2e5bd 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -52,6 +52,7 @@ #include <linux/poll.h> #include <linux/ratelimit.h> #include <linux/sched.h> +#include <linux/seqlock.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/vmalloc.h> @@ -392,11 +393,6 @@ struct drm_master { void *driver_priv; }; -/* Size of ringbuffer for vblank timestamps. Just double-buffer - * in initial implementation. - */ -#define DRM_VBLANKTIME_RBSIZE 2 - /* Flags and return codes for get_vblank_timestamp() driver function. */ #define DRM_CALLED_FROM_VBLIRQ 1 #define DRM_VBLANKTIME_SCANOUTPOS_METHOD (1 << 0) @@ -725,10 +721,10 @@ struct drm_vblank_crtc { wait_queue_head_t queue; /**< VBLANK wait queue */ struct timer_list disable_timer; /* delayed disable timer */ - /* vblank counter, protected by dev->vblank_time_lock for writes */ - u32 count; - /* vblank timestamps, protected by dev->vblank_time_lock for writes */ - struct timeval time[DRM_VBLANKTIME_RBSIZE]; + seqlock_t seqlock; /* protects vblank count and time */ + + u32 count; /* vblank counter */ + struct timeval time; /* vblank timestamp */ atomic_t refcount; /* number of users of vblank interruptsper crtc */ u32 last; /* protected by dev->vbl_lock, used */ |