drm/exynos/decon5433: wait for two vblanks before framebuffer removal

After window disable DECON can access its DMA buffer in current and next
scanout. To avoid possible page fault driver should ensure that two scanouts
passed before freeing framebuffer.

Change-Id: I5508f6686ff51d555eb1497b7a6d21b990fd6003
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>

diff --git a/drivers/gpu/drm/exynos/exynos5433_drm_decon.c b/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
index e22bc0f..0d6c368 100644 (file)
--- a/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
+++ b/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
@@ -94,7 +94,7 @@ static void decon_wait_for_vblank(struct exynos_drm_crtc *crtc)
        if (ctx->suspended)
                return;
 
-       atomic_set(&ctx->wait_vsync_event, 1);
+       atomic_set(&ctx->wait_vsync_event, 2);
 
        /*
         * wait for FIMD to signal VSYNC interrupt or return after
@@ -658,7 +658,7 @@ static void decon_clear_channel(struct decon_context *ctx)
 
        decon_update(ctx);
 
-       atomic_set(&ctx->wait_vsync_event, 1);
+       atomic_set(&ctx->wait_vsync_event, 2);
 
        /*
         * wait for FIMD to signal VSYNC interrupt or return after
@@ -753,7 +753,7 @@ static irqreturn_t decon_irq_handler(int irq, void *dev_id)
 
 out:
        if (atomic_read(&ctx->wait_vsync_event)) {
-               atomic_set(&ctx->wait_vsync_event, 0);
+               atomic_dec_if_positive(&ctx->wait_vsync_event);
                wake_up(&ctx->wait_vsync_queue);
        }