shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-06 02:50:49 +09:00
Code Issues Packages Projects Releases Wiki Activity

vb2: fix a regression in poll() behavior for output,streams

Browse Source 
commit 4623e59674 upstream.

In the 3.17 kernel the poll() behavior changed for output streams:
as long as not all buffers were queued up poll() would return that
userspace can write. This is fine for the write() call, but when
using stream I/O this changed the behavior since the expectation
was that it would wait for buffers to become available for dequeuing.

This patch only enables the check whether you can queue buffers
for file I/O only, and skips it for stream I/O.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hans Verkuil
2015-10-29 03:02:06 -02:00
committed by Greg Kroah-Hartman
parent f51c5d31c8
commit 368e554ba6
1 changed files with 3 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/media/v4l2-core/videobuf2-v4l2.c
View File

@@ -822,10 +822,10 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
return res | POLLERR;
/*
* For output streams you can write as long as there are fewer buffers
* queued than there are buffers available.
* For output streams you can call write() as long as there are fewer
* buffers queued than there are buffers available.
*/
if (q->is_output && q->queued_count < q->num_buffers)
if (q->is_output && q->fileio && q->queued_count < q->num_buffers)
return res | POLLOUT | POLLWRNORM;
if (list_empty(&q->done_list)) {