On 2016?04?01? 19:47, Tomeu Vizoso wrote: > On 04/01/2016 01:26 PM, Mark yao wrote: >> On 2016?03?31? 16:08, 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". >>> >>> v2: Use the status of the workqueue instead of vop->event, and don't add >>> a superfluous wait on the workqueue. >>> >>> Signed-off-by: Tomeu Vizoso <tomeu.vizoso at collabora.com> >>> --- >>> drivers/gpu/drm/rockchip/rockchip_drm_fb.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c >>> index 3b8f652698f8..285f8cd5afe1 100644 >>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c >>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c >>> @@ -282,6 +282,9 @@ int rockchip_drm_atomic_commit(struct drm_device *dev, >>> struct rockchip_atomic_commit *commit = &private->commit; >>> int ret; >>> >>> + if (async && work_busy(&commit->work)) >>> + return -EBUSY; >>> + >> Sorry for reply late. >> >> There is a comment on work_busy function describe : >> >> "the test result is unreliable and only useful as advisory hints or >> for debugging." >> >> I don't know if it's suitable to use it here, does some guys know it? > I'm not sure, but if the reason is the caveat explained in > find_worker_executing_work(), then it's probably safe (and would explain > how the function is used in other parts in the kernel). > >> And then, the "flush_work(&commit->work);" is no needed if return -EBUSY >> here. >> you can remove it at this patch. > We still need to wait if it's being called in sync mode. > > Regards, > > Tomeu Hi Tomeu?? on sync mode, flush is no needed, because that: 1, there is mutex_lock/mutex_unlock on this context, So only single process run into commit work; 2, sync mode will block on: rockchip_atomic_commit_complete-->rockchip_atomic_wait_for_complete, Thanks. > >>> ret = drm_atomic_helper_prepare_planes(dev, state); >>> if (ret) >>> return ret; >> >> >> -- >> ?ark Yao >> > > > -- ?ark Yao
