drm/exynos: modify wait_for_vblank of fimd
It is more optimium to use wait queues while waiting for vsync so
that the current task is put to sleep. This way, the task wont
hog the CPU while waiting. We use wait_event_timeout and not
an interruptible function since we dont want the function to exit
when a signal is pending (e.g. drm release). This patch modifies
the wait for vblank function of fimd.
Signed-off-by: Prathyush K <prathyush.k@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 1d46286..1517d15 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -100,6 +100,8 @@
u32 vidcon1;
bool suspended;
struct mutex lock;
+ wait_queue_head_t wait_vsync_queue;
+ atomic_t wait_vsync_event;
struct exynos_drm_panel_info *panel;
};
@@ -311,11 +313,19 @@
static void fimd_wait_for_vblank(struct device *dev)
{
struct fimd_context *ctx = get_fimd_context(dev);
- int ret;
- ret = wait_for((__raw_readl(ctx->regs + VIDCON1) &
- VIDCON1_VSTATUS_VSYNC), 50);
- if (ret < 0)
+ if (ctx->suspended)
+ return;
+
+ atomic_set(&ctx->wait_vsync_event, 1);
+
+ /*
+ * wait for FIMD to signal VSYNC interrupt or return after
+ * timeout which is set to 50ms (refresh rate of 20).
+ */
+ if (!wait_event_timeout(ctx->wait_vsync_queue,
+ !atomic_read(&ctx->wait_vsync_event),
+ DRM_HZ/20))
DRM_DEBUG_KMS("vblank wait timed out.\n");
}
@@ -667,6 +677,11 @@
drm_handle_vblank(drm_dev, manager->pipe);
fimd_finish_pageflip(drm_dev, manager->pipe);
+ /* set wait vsync event to zero and wake up queue. */
+ if (atomic_read(&ctx->wait_vsync_event)) {
+ atomic_set(&ctx->wait_vsync_event, 0);
+ DRM_WAKEUP(&ctx->wait_vsync_queue);
+ }
out:
return IRQ_HANDLED;
}
@@ -885,6 +900,8 @@
ctx->vidcon1 = pdata->vidcon1;
ctx->default_win = pdata->default_win;
ctx->panel = panel;
+ DRM_INIT_WAITQUEUE(&ctx->wait_vsync_queue);
+ atomic_set(&ctx->wait_vsync_event, 0);
subdrv = &ctx->subdrv;
