V4L/DVB: uvcvideo: Use POLLOUT and POLLWRNORM for output devices

The V4L2 specification requires drivers to use the write events in the
file operations poll handler for output devices. The uvcvideo driver
erroneously used read events for all devices. Fix this.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/media/video/uvc/uvc_queue.c b/drivers/media/video/uvc/uvc_queue.c
index 4a925a31b0e0..133c78d113ac 100644
--- a/drivers/media/video/uvc/uvc_queue.c
+++ b/drivers/media/video/uvc/uvc_queue.c
@@ -388,8 +388,12 @@ unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
 
         poll_wait(file, &buf->wait, wait);
         if (buf->state == UVC_BUF_STATE_DONE ||
-            buf->state == UVC_BUF_STATE_ERROR)
-                mask |= POLLIN | POLLRDNORM;
+            buf->state == UVC_BUF_STATE_ERROR) {
+                if (queue->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
+                        mask |= POLLIN | POLLRDNORM;
+                else
+                        mask |= POLLOUT | POLLWRNORM;
+        }
 
 done:
         mutex_unlock(&queue->mutex);