I found this while testing the vb2 conversion of bw-qcam. Without this change select() will always return when polling for events only. If you only poll for events, then vb2_poll will return 'res | POLLERR' if no streaming is in progress. That's not right, it's perfectly valid to poll just for events. Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> Regards, Hans --- drivers/media/v4l2-core/videobuf2-core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index d09be38..db1235d 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1965,6 +1965,11 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) poll_wait(file, &fh->wait, wait); } + if (!V4L2_TYPE_IS_OUTPUT(q->type) && !(req_events & (POLLIN | POLLRDNORM))) + return res; + if (V4L2_TYPE_IS_OUTPUT(q->type) && !(req_events & (POLLOUT | POLLWRNORM))) + return res; + /* * Start file I/O emulator only if streaming API has not been used yet. */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
