summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/drm_irq.c
diff options
context:
space:
mode:
authorVille Syrjälä <ville.syrjala@linux.intel.com>2015-09-14 22:43:44 +0300
committerDaniel Vetter <daniel.vetter@ffwll.ch>2015-09-24 20:14:21 +0200
commit3bb403bf421b5b00366a9041a7edc0a1f6494f5e (patch)
treed280555ef17c89c2a1e952d03749d230547598c3 /drivers/gpu/drm/drm_irq.c
parenteba1f35dfe145247c7eb690c7c32740fde8ec699 (diff)
drm: Stop using linedur_ns and pixeldur_ns for vblank timestamps
linedur_ns, and especially pixeldur_ns are becoming rather inaccurate to be used for the vblank timestamp correction. With 4k@60 the pixel duration is already below 2ns, so the amount of error due to the truncation to nanoseconds is introducing quite a bit of error. We can avoid such problems if we instead calculate the timestamp delta_ns directly from the dislay timings, avoiding the use of these intermediate truncated values. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> [danvet: Squash in fixup from Thierry Reding for amdgpu.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/drm_irq.c')
-rw-r--r--drivers/gpu/drm/drm_irq.c19
1 files changed, 8 insertions, 11 deletions
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 6b2fefde25a8..9fab3334eb6b 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -694,12 +694,11 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
unsigned flags,
const struct drm_display_mode *mode)
{
- struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
struct timeval tv_etime;
ktime_t stime, etime;
int vbl_status;
int vpos, hpos, i;
- int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
+ int delta_ns, duration_ns;
bool invbl;
if (pipe >= dev->num_crtcs) {
@@ -713,15 +712,10 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
return -EIO;
}
- /* Durations of frames, lines, pixels in nanoseconds. */
- framedur_ns = vblank->framedur_ns;
- linedur_ns = vblank->linedur_ns;
- pixeldur_ns = vblank->pixeldur_ns;
-
/* If mode timing undefined, just return as no-op:
* Happens during initial modesetting of a crtc.
*/
- if (framedur_ns == 0) {
+ if (mode->crtc_clock == 0) {
DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
return -EAGAIN;
}
@@ -738,8 +732,10 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
* Get vertical and horizontal scanout position vpos, hpos,
* and bounding timestamps stime, etime, pre/post query.
*/
- vbl_status = dev->driver->get_scanout_position(dev, pipe, flags, &vpos,
- &hpos, &stime, &etime);
+ vbl_status = dev->driver->get_scanout_position(dev, pipe, flags,
+ &vpos, &hpos,
+ &stime, &etime,
+ mode);
/* Return as no-op if scanout query unsupported or failed. */
if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
@@ -776,7 +772,8 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
* since start of scanout at first display scanline. delta_ns
* can be negative if start of scanout hasn't happened yet.
*/
- delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
+ delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
+ mode->crtc_clock);
if (!drm_timestamp_monotonic)
etime = ktime_mono_to_real(etime);