On Fri, Aug 02, 2019 at 05:29:20PM +0800, Brian Starkey wrote: > Hi Lowry, > > On Thu, Aug 01, 2019 at 06:34:08AM +0000, Lowry Li (Arm Technology China) wrote: > > Hi Brian, > > > > On Wed, Jul 31, 2019 at 09:20:04PM +0800, Brian Starkey wrote: > > > Hi Lowry, > > > > > > Thanks for this cleanup. > > > > > > On Wed, Jul 31, 2019 at 11:04:45AM +0000, Lowry Li (Arm Technology China) wrote: > > > > During it signals the completion of a writeback job, after releasing > > > > the out_fence, we'd clear the pointer. > > > > > > > > Check if fence left over in drm_writeback_cleanup_job(), release it. > > > > > > > > Signed-off-by: Lowry Li (Arm Technology China) <lowry.li@xxxxxxx> > > > > --- > > > > drivers/gpu/drm/drm_writeback.c | 23 +++++++++++++++-------- > > > > 1 file changed, 15 insertions(+), 8 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c > > > > index ff138b6..43d9e3b 100644 > > > > --- a/drivers/gpu/drm/drm_writeback.c > > > > +++ b/drivers/gpu/drm/drm_writeback.c > > > > @@ -324,6 +324,9 @@ void drm_writeback_cleanup_job(struct drm_writeback_job *job) > > > > if (job->fb) > > > > drm_framebuffer_put(job->fb); > > > > > > > > + if (job->out_fence) > > > > > > I'm thinking it might be a good idea to signal the fence with an error > > > here, if it's not already signaled. Otherwise, if there's someone > > > waiting (which there shouldn't be), they're going to be waiting a very > > > long time :-) > > > > > > Thanks, > > > -Brian > > > > > Here it happened at atomic_check failed and test only commit. For both > > cases, the commit has been dropped and it's only a clean up. So here better > > not be treated as an error case:) > > If anyone else has a reference on the fence, then IMO it absolutely is > an error to reach this point without the fence being signaled - > because it means that the fence will never be signaled. > > I don't think the API gives you a way to check if this is the last > reference, so it's safest to just make sure the fence is signalled > before dropping the reference. > > It just feels wrong to me to have the possibility of a dangling fence > which is never going to get signalled; and it's an easy defensive step > to make sure it can never happen. > > I know it _shouldn't_ happen, but we often put in handling for cases > which shouldn't happen, because they frequently do happen :-) > > > > > Since for userspace, it should have been failed or a test only case, so > > writebace fence should not be signaled. > > It's not only userspace that can wait on fences (and in fact this > fence will never even reach userspace if the commit fails), the driver > may have taken a copy to use for "something". > Maybe we can add a wb_fence canceling into complete_signaling() for the atomic_check failed cleanup like the crtc->out_fence. Then if in this place we still can got a fence here, that must be a error we signal and WARN it Thanks James > Cheers, > -Brian > > > > > Best regards, > > Lowry > > > > + dma_fence_put(job->out_fence); > > > > + > > > > kfree(job); > > > > } > > > > -- > > Regards > > Lowry _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
