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@xxxxxxx>
---
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 6469f9a25a4e..837e1855f94b 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);
--
2.36.1
