Re: [PATCH] drm/rockchip: Return -EBUSY if there's already a pending flip event

From: Mark yao
Date: Wed Mar 30 2016 - 21:25:56 EST

On 2016å03æ30æ 21:48, Tomeu Vizoso wrote:
As per the docs, atomic_commit should return -EBUSY "if an asycnhronous
updated is requested and there is an earlier updated pending".

Also wait for the pending event to complete when a sync update is

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
drivers/gpu/drm/rockchip/rockchip_drm_drv.h | 1 +
drivers/gpu/drm/rockchip/rockchip_drm_fb.c | 14 +++++++++++++-
drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 6 ++++++
3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
index 3529f692edb8..37952eefd33d 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
@@ -69,6 +69,7 @@ int rockchip_register_crtc_funcs(struct drm_crtc *crtc,
void rockchip_unregister_crtc_funcs(struct drm_crtc *crtc);
int rockchip_drm_crtc_mode_config(struct drm_crtc *crtc, int connector_type,
int out_mode);
+bool rockchip_drm_crtc_has_pending_event(struct drm_crtc *crtc);
int rockchip_drm_dma_attach_device(struct drm_device *drm_dev,
struct device *dev);
void rockchip_drm_dma_detach_device(struct drm_device *drm_dev,
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
index 3b8f652698f8..028fd2f8f47b 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
@@ -280,7 +280,19 @@ int rockchip_drm_atomic_commit(struct drm_device *dev,
struct rockchip_drm_private *private = dev->dev_private;
struct rockchip_atomic_commit *commit = &private->commit;
- int ret;
+ struct drm_crtc_state *crtc_state;
+ struct drm_crtc *crtc;
+ int i, ret;
+ for_each_crtc_in_state(state, crtc, crtc_state, i) {
+ if (crtc->state->event ||
+ rockchip_drm_crtc_has_pending_event(crtc)) {
+ if (async)
+ return -EBUSY;
+ else
+ rockchip_crtc_wait_for_update(crtc);

+ }
+ }
ret = drm_atomic_helper_prepare_planes(dev, state);
if (ret)
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index e2118e62345b..5240bc8fe088 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -848,6 +848,12 @@ int rockchip_drm_crtc_mode_config(struct drm_crtc *crtc,
+bool rockchip_drm_crtc_has_pending_event(struct drm_crtc *crtc)
+ return to_vop(crtc)->event;

No need to do EXPORT_SYMBOL_GPL, rockchip_drm_vop.c and rockchip_drm_fb.c will build into same object.

static int vop_crtc_enable_vblank(struct drm_crtc *crtc)
struct vop *vop = to_vop(crtc);
Hi Tomeu

Since rockchip atomic async use "serialize outstanding asynchronous commits", async commit will wait on "flush_work(&commit->work);" to ensure last pending event is done, so vop->event should be NULL after flush. if not, it should be a BUG.

Anyway, serialize async commits is not a good way, but I don't think your patch is better way.

I think maybe we can check the "commit->work" status(finish or running) to judge return BUSY or not, instead of flush it.


ïark Yao