On 04/22/2016 11:47 AM, Ricardo Ribalda Delgado wrote: > Thanks for your review! > > I will fix it that way. Do you mind to wait until Monday for a patch? No problem. Hans > > Regards > > On 22 Apr 2016 11:19, "Hans Verkuil" <hverkuil@xxxxxxxxx <mailto:hverkuil@xxxxxxxxx>> wrote: > > Hi Ricardo, > > On 04/21/2016 11:15 AM, Ricardo Ribalda Delgado wrote: > > When using a device is read/write mode, vb2 does not handle properly the > > first select/poll operation. It allways return POLLERR. > > > > The reason for this is that when this code has been refactored, some of > > the operations have changed their order, and now fileio emulator is not > > started by poll, due to a previous check. > > > > Reported-by: Dimitrios Katsaros <patcherwork@xxxxxxxxx <mailto:patcherwork@xxxxxxxxx>> > > Cc: Junghak Sung <jh1009.sung@xxxxxxxxxxx <mailto:jh1009.sung@xxxxxxxxxxx>> > > Cc: stable@xxxxxxxxxxxxxxx <mailto:stable@xxxxxxxxxxxxxxx> > > Fixes: 49d8ab9feaf2 ("media] media: videobuf2: Separate vb2_poll()") > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx <mailto:ricardo.ribalda@xxxxxxxxx>> > > --- > > drivers/media/v4l2-core/videobuf2-core.c | 8 ++++++++ > > drivers/media/v4l2-core/videobuf2-v4l2.c | 8 -------- > > 2 files changed, 8 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c > > index 5d016f496e0e..199c65dbe330 100644 > > --- a/drivers/media/v4l2-core/videobuf2-core.c > > +++ b/drivers/media/v4l2-core/videobuf2-core.c > > @@ -2298,6 +2298,14 @@ unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file, > > return POLLERR; > > > > /* > > + * For compatibility with vb1: if QBUF hasn't been called yet, then > > + * return POLLERR as well. This only affects capture queues, output > > + * queues will always initialize waiting_for_buffers to false. > > + */ > > + if (q->waiting_for_buffers && (req_events & (POLLIN | POLLRDNORM))) > > + return POLLERR; > > The problem I have with this is that this should be specific to V4L2. The only > reason we do this is that we had to stay backwards compatible with vb1. > > This is the reason this code was placed in videobuf2-v4l2.c. But you are correct > that this causes a regression, and I see no other choice but to put it in core.c. > > That said, I would still only honor this when called from v4l2, so I suggest that > a new flag 'check_waiting_for_buffers' is added that is only set in vb2_queue_init > in videobuf2-v4l2.c. > > So the test above becomes: > > if (q->check_waiting_for_buffers && q->waiting_for_buffers && > (req_events & (POLLIN | POLLRDNORM))) > > It's not ideal, but at least this keeps this v4l2 specific. > > Regards, > > Hans > > > + > > + /* > > * For output streams you can call write() as long as there are fewer > > * buffers queued than there are buffers available. > > */ > > diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c > > index 91f552124050..c9bad9ef2104 100644 > > --- a/drivers/media/v4l2-core/videobuf2-v4l2.c > > +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c > > @@ -818,14 +818,6 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) > > poll_wait(file, &fh->wait, wait); > > } > > > > - /* > > - * For compatibility with vb1: if QBUF hasn't been called yet, then > > - * return POLLERR as well. This only affects capture queues, output > > - * queues will always initialize waiting_for_buffers to false. > > - */ > > - if (q->waiting_for_buffers && (req_events & (POLLIN | POLLRDNORM))) > > - return POLLERR; > > - > > return res | vb2_core_poll(q, file, wait); > > } > > EXPORT_SYMBOL_GPL(vb2_poll); > > > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html