From d4de27a9b1eadd33a2e40de87a646d1bf5fef756 Mon Sep 17 00:00:00 2001 From: Ming Qian Date: Wed, 15 Jun 2022 04:19:20 +0100 Subject: [PATCH] media: v4l2-mem2mem: prevent pollerr when last_buffer_dequeued is set 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 Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- 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 6469f9a..837e185 100644 --- a/drivers/media/v4l2-core/v4l2-mem2mem.c +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c @@ -925,7 +925,7 @@ 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); -- 2.7.4