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-rw-r--r--drivers/gpu/drm/vkms/vkms_crtc.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 7508815fac11..1bbe099b7db8 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -15,6 +15,10 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
spin_lock(&output->lock);
+ ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
+ output->period_ns);
+ WARN_ON(ret_overrun != 1);
+
ret = drm_crtc_handle_vblank(crtc);
if (!ret)
DRM_ERROR("vkms failure on handling vblank");
@@ -35,10 +39,6 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
DRM_WARN("failed to queue vkms_crc_work_handle");
}
- ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
- output->period_ns);
- WARN_ON(ret_overrun != 1);
-
spin_unlock(&output->lock);
return HRTIMER_RESTART;
@@ -74,11 +74,21 @@ bool vkms_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
{
struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
struct vkms_output *output = &vkmsdev->output;
+ struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
*vblank_time = output->vblank_hrtimer.node.expires;
- if (!in_vblank_irq)
- *vblank_time -= output->period_ns;
+ if (WARN_ON(*vblank_time == vblank->time))
+ return true;
+
+ /*
+ * To prevent races we roll the hrtimer forward before we do any
+ * interrupt processing - this is how real hw works (the interrupt is
+ * only generated after all the vblank registers are updated) and what
+ * the vblank core expects. Therefore we need to always correct the
+ * timestampe by one frame.
+ */
+ *vblank_time -= output->period_ns;
return true;
}