Hello Alex, Thanks for the patch. On Tue, Aug 25, 2020, 11:56 AM Alexandre Courbot <gnurou@xxxxxxxxx> wrote: > > This addresses a very corner case that probably nobody ever encounters, > but I have hit it when playing with vicoded so here is a tentative fix. > I'll try to make a more complete review soon, but meanwhile I was thinking if it was possible to include a little kselftest program for this issue, something CIs can pick-up and test corner cases like this, making sure we don't regress on the issue. (Or alternatively, v4l2-compliance?) Thanks! Ezequiel > Patch 1/2 addresses the issue that when the last buffer of a m2m device > has been dequeued, any attempt to poll with EPOLLOUT will result in only > EPOLLIN being returned, even if OUTPUT buffers are still pending. The > issue stems from the fact that the last buffer check if done first, and > returns immediately if true. > > Patch 2/2 builds on the first one to (hopefully) clean up the code a bit > and make the function flow easier to follow. Functionally speaking it is > supposed to be a no-op and it can safely be dropped if the former code > is preferred - the actual fix is in 1/2. > > Alexandre Courbot (2): > media: v4l2-mem2mem: consider OUTPUT queue first when polling > media: v4l2-mem2mem: simplify poll logic a bit > > drivers/media/v4l2-core/v4l2-mem2mem.c | 42 +++++++++++--------------- > 1 file changed, 18 insertions(+), 24 deletions(-) > > -- > 2.28.0 >
