[PATCH] drm/exynos: wait for the completion of pending page flip

[Inki Dae]

This patch fixes the issue that drm_vblank_get() is failed.

The issus occurs when next page flip request is tried
if previous page flip event wasn't completed yet and then
dpms became off.

So this patch make sure that page flip event is completed
before dpms goes to off.

Signed-off-by: Inki Dae <inki....@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_crtc.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c 
b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index e8894bc..69a77e9 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -48,6 +48,8 @@ struct exynos_drm_crtc {
        unsigned int                    pipe;
        unsigned int                    dpms;
        enum exynos_crtc_mode           mode;
+       wait_queue_head_t               pending_flip_queue;
+       atomic_t                        pending_flip;
 };
 
 static void exynos_drm_crtc_dpms(struct drm_crtc *crtc, int mode)
@@ -61,6 +63,13 @@ static void exynos_drm_crtc_dpms(struct drm_crtc *crtc, int 
mode)
                return;
        }
 
+       if (mode > DRM_MODE_DPMS_ON) {
+               /* wait for the completion of page flip. */
+               wait_event(exynos_crtc->pending_flip_queue,
+                               atomic_read(&exynos_crtc->pending_flip) == 0);
+               drm_vblank_off(crtc->dev, exynos_crtc->pipe);
+       }
+
        exynos_drm_fn_encoder(crtc, &mode, exynos_drm_encoder_crtc_dpms);
        exynos_crtc->dpms = mode;
 }
@@ -225,6 +234,7 @@ static int exynos_drm_crtc_page_flip(struct drm_crtc *crtc,
                spin_lock_irq(&dev->event_lock);
                list_add_tail(&event->base.link,
                                &dev_priv->pageflip_event_list);
+               atomic_set(&exynos_crtc->pending_flip, 1);
                spin_unlock_irq(&dev->event_lock);
 
                crtc->fb = fb;
@@ -344,6 +354,8 @@ int exynos_drm_crtc_create(struct drm_device *dev, unsigned 
int nr)
 
        exynos_crtc->pipe = nr;
        exynos_crtc->dpms = DRM_MODE_DPMS_OFF;
+       init_waitqueue_head(&exynos_crtc->pending_flip_queue);
+       atomic_set(&exynos_crtc->pending_flip, 0);
        exynos_crtc->plane = exynos_plane_init(dev, 1 << nr, true);
        if (!exynos_crtc->plane) {
                kfree(exynos_crtc);
@@ -398,6 +410,8 @@ void exynos_drm_crtc_finish_pageflip(struct drm_device 
*dev, int crtc)
 {
        struct exynos_drm_private *dev_priv = dev->dev_private;
        struct drm_pending_vblank_event *e, *t;
+       struct drm_crtc *drm_crtc = dev_priv->crtc[crtc];
+       struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(drm_crtc);
        struct timeval now;
        unsigned long flags;
 
@@ -419,6 +433,8 @@ void exynos_drm_crtc_finish_pageflip(struct drm_device 
*dev, int crtc)
                list_move_tail(&e->base.link, &e->base.file_priv->event_list);
                wake_up_interruptible(&e->base.file_priv->event_wait);
                drm_vblank_put(dev, crtc);
+               atomic_set(&exynos_crtc->pending_flip, 0);
+               wake_up(&exynos_crtc->pending_flip_queue);
        }
 
        spin_unlock_irqrestore(&dev->event_lock, flags);
-- 
1.7.5.4

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