From: Ming Qian <ming.qian@nxp.com> stable inclusion from stable-v5.10.137 commit 7f7336ce35682f911b67c9162f4b301c9ee99ab1 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit d4de27a9b1eadd33a2e40de87a646d1bf5fef756 ] If the last buffer was dequeued from the capture queue, signal userspace. DQBUF(CAPTURE) will return -EPIPE. But if output queue is empty and capture queue is empty, v4l2_m2m_poll_for_data will return EPOLLERR, This is very easy to happen in drain. When last_buffer_dequeued is set, we shouldn't return EPOLLERR, but return EPOLLIN | EPOLLRDNORM. Fixes: 1698a7f151126 ("media: v4l2-mem2mem: simplify poll logic") Signed-off-by: Ming Qian <ming.qian@nxp.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> --- drivers/media/v4l2-core/v4l2-mem2mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c index 73190652c267..ad14d5214106 100644 --- a/drivers/media/v4l2-core/v4l2-mem2mem.c +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c @@ -927,7 +927,7 @@ static __poll_t v4l2_m2m_poll_for_data(struct file *file, if ((!src_q->streaming || src_q->error || list_empty(&src_q->queued_list)) && (!dst_q->streaming || dst_q->error || - list_empty(&dst_q->queued_list))) + (list_empty(&dst_q->queued_list) && !dst_q->last_buffer_dequeued))) return EPOLLERR; spin_lock_irqsave(&src_q->done_lock, flags); -- 2.20.1