As per the docs, atomic_commit should return -EBUSY "if an asycnhronous
updated is requested and there is an earlier updated pending".
v2: Use the status of the workqueue instead of vop->event, and don't add
a superfluous wait on the workqueue.
v3: Drop work_busy, as there's a sizeable delay when the worker
finishes, which introduces a race in which the client has already
received the last flip event but the next page flip ioctl will still
return -EBUSY because work_busy returns outdated information.
Signed-off-by: Tomeu Vizoso <[email protected]>
---
drivers/gpu/drm/rockchip/rockchip_drm_drv.h | 1 +
drivers/gpu/drm/rockchip/rockchip_drm_fb.c | 13 ++++++++++++-
drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 5 +++++
3 files changed, 18 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..8305bbd2a4d7 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
@@ -280,7 +280,18 @@ 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;
+
+ if (async) {
+ for_each_crtc_in_state(state, crtc, crtc_state, i) {
+ if (crtc->state->event ||
+ rockchip_drm_crtc_has_pending_event(crtc)) {
+ return -EBUSY;
+ }
+ }
+ }
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..5bcdd8dc7499 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -848,6 +848,11 @@ int rockchip_drm_crtc_mode_config(struct drm_crtc *crtc,
}
EXPORT_SYMBOL_GPL(rockchip_drm_crtc_mode_config);
+bool rockchip_drm_crtc_has_pending_event(struct drm_crtc *crtc)
+{
+ return to_vop(crtc)->event;
+}
+
static int vop_crtc_enable_vblank(struct drm_crtc *crtc)
{
struct vop *vop = to_vop(crtc);
--
2.5.5
Hi Tomeu,
On 4 April 2016 at 14:55, Tomeu Vizoso <[email protected]> wrote:
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
> index 3b8f652698f8..8305bbd2a4d7 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
> @@ -280,7 +280,18 @@ 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;
> +
> + if (async) {
> + for_each_crtc_in_state(state, crtc, crtc_state, i) {
> + if (crtc->state->event ||
> + rockchip_drm_crtc_has_pending_event(crtc)) {
> + return -EBUSY;
> + }
> + }
> + }
Hmmm ...
Doesn't this trigger before the VOP atomic_begin() helper, meaning
that anything with an event set will trigger the check? Seems like it
should be && rather than ||.
Also, I know rockchip_drm_vop.c isn't holding dev->event_lock when it
checks vop->event, but it really should be ... and so should this
check. Otherwise you can race with the IRQ handler, which isn't
required to hold the CRTC lock.
Cheers,
Daniel
On 4 April 2016 at 17:44, Daniel Stone <[email protected]> wrote:
> Hi Tomeu,
>
> On 4 April 2016 at 14:55, Tomeu Vizoso <[email protected]> wrote:
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
>> index 3b8f652698f8..8305bbd2a4d7 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
>> @@ -280,7 +280,18 @@ 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;
>> +
>> + if (async) {
>> + for_each_crtc_in_state(state, crtc, crtc_state, i) {
>> + if (crtc->state->event ||
>> + rockchip_drm_crtc_has_pending_event(crtc)) {
>> + return -EBUSY;
>> + }
>> + }
>> + }
>
> Hmmm ...
>
> Doesn't this trigger before the VOP atomic_begin() helper, meaning
> that anything with an event set will trigger the check? Seems like it
> should be && rather than ||.
So, these are the two cases that this code aims to handle:
1. A previous request with an event set hasn't progressed to
atomic_begin yet, so the event field in drm_crtc_state (at this point,
the old state) is still populated but vop->event still isn't.
2. A previous request has already progressed to atomic_begin but we
haven't gotten yet the interrupt that signals its completion, so
vop->event is populated but crtc->state->event isn't anymore.
My understanding is that in both cases there's a pending flip event
and we have to return -EBUSY if it's as async request.
> Also, I know rockchip_drm_vop.c isn't holding dev->event_lock when it
> checks vop->event, but it really should be ... and so should this
> check. Otherwise you can race with the IRQ handler, which isn't
> required to hold the CRTC lock.
Cool, thanks.
Tomeu
> Cheers,
> Daniel
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