From 000fa7cf46479238f7b9f2d7763e41af5268b16a Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Fri, 10 Dec 2010 16:00:19 +0100 Subject: [PATCH] drm-vblank: Always return true vblank count of scheduled vblank event. This patch tries to make sure that the vbl.reply.sequence vblank count for a queued or emitted vblank event always corresponds to the true vblank count of queueing/emission, so the ddx can rely on the returned target_msc for consistency checks and implementation of swap_intervals in glXSwapBuffers(). Without this there is a small race-condition between the userspace ddx queueing a vblank event and the vblank counter incrementing before the event gets queued in the kernel. Signed-off-by: Mario Kleiner Acked-by: Jesse Barnes Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_irq.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 4e82d0d..55160d7 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1086,15 +1086,18 @@ static int drm_queue_vblank_event(struct drm_device *dev, int pipe, e->event.sequence = vblwait->request.sequence; if ((seq - vblwait->request.sequence) <= (1 << 23)) { + e->event.sequence = seq; e->event.tv_sec = now.tv_sec; e->event.tv_usec = now.tv_usec; drm_vblank_put(dev, e->pipe); list_add_tail(&e->base.link, &e->base.file_priv->event_list); wake_up_interruptible(&e->base.file_priv->event_wait); + vblwait->reply.sequence = seq; trace_drm_vblank_event_delivered(current->pid, pipe, vblwait->request.sequence); } else { list_add_tail(&e->base.link, &dev->vblank_event_list); + vblwait->reply.sequence = vblwait->request.sequence; } spin_unlock_irqrestore(&dev->event_lock, flags); -- 2.7.4