[SCM] libav/experimental: In the video4linux2 output device, log an error description in case of ioctl failure in mmap_release_buffer().

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit bd7d9e45a44480da09e956b55e93f455cf1ed26c
Author: Stefano Sabatini <stefano.sabatini-lala at poste.it>
Date:   Tue Jan 4 18:18:01 2011 +0000

    In the video4linux2 output device, log an error description in case of
    ioctl failure in mmap_release_buffer().
    
    Originally committed as revision 26214 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavdevice/v4l2.c b/libavdevice/v4l2.c
index 035e416..5425928 100644
--- a/libavdevice/v4l2.c
+++ b/libavdevice/v4l2.c
@@ -324,7 +324,7 @@ static void mmap_release_buffer(AVPacket *pkt)
 
     res = ioctl(fd, VIDIOC_QBUF, &buf);
     if (res < 0) {
-        av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF)\n");
+        av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno));
     }
     pkt->data = NULL;
     pkt->size = 0;

-- 
Libav/FFmpeg packaging