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drm/vblank: Data type fixes for 64-bit vblank sequences. 

drm_vblank_count() has an u32 type returning what is a 64-bit vblank count.
The effect of this is when drm_wait_vblank_ioctl() tries to widen the user
space requested vblank sequence using this clipped 32-bit count(when the
value is >= 2^32) as reference, the requested sequence remains a 32-bit
value and gets queued like that. However, the code that checks if the
requested sequence has passed compares this against the 64-bit vblank
count.

With drm_vblank_count() returning all bits of the vblank count, update
drm_crtc_accurate_vblank_count() so that drm_crtc_arm_vblank_event() queues
the correct sequence. Otherwise, this leads to prolonged waits for a vblank
sequence when the current count is >=2^32.

Finally, fix drm_wait_one_vblank() too.

v2: Commit message fix (Keith)
    Squash commits (Rodrigo)

Fixes: 570e86963a ("drm: Widen vblank count to 64-bits [v3]")
Cc: Keith Packard <keithp@keithp.com>
Cc: Michel Dänzer <michel@daenzer.net>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180203051302.9974-1-dhinakaran.pandiyan@intel.com
hifive-unleashed-5.1
Dhinakaran Pandiyan 2018-02-02 21:12:53 -08:00 committed by Rodrigo Vivi
parent 6e8c06d291
commit 3b765c0b76
2 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/gpu/drm/drm_vblank.c
View File

@ -271,7 +271,7 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
store_vblank(dev, pipe, diff, t_vblank, cur_vblank);
}
static u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
static u64 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
@ -292,11 +292,11 @@ static u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
* This is mostly useful for hardware that can obtain the scanout position, but
* doesn't have a hardware frame counter.
*/
u32 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
{
struct drm_device *dev = crtc->dev;
unsigned int pipe = drm_crtc_index(crtc);
u32 vblank;
u64 vblank;
unsigned long flags;
WARN_ONCE(drm_debug & DRM_UT_VBL && !dev->driver->get_vblank_timestamp,
@ -1055,7 +1055,7 @@ void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
int ret;
u32 last;
u64 last;
if (WARN_ON(pipe >= dev->num_crtcs))
return;

2
include/drm/drm_vblank.h
View File

@ -179,7 +179,7 @@ void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
void drm_crtc_vblank_off(struct drm_crtc *crtc);
void drm_crtc_vblank_reset(struct drm_crtc *crtc);
void drm_crtc_vblank_on(struct drm_crtc *crtc);
u32 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
unsigned int pipe, int *max_error,