gst-plugins-good: v4l2src: fix v4l2_munmap() for compressed formats

[Tim Müller]

Module: gst-plugins-good
Branch: master
Commit: 4cd9255f0a8a9e15d81561f00f02d275b5095f70
URL:    http://cgit.freedesktop.org/gstreamer/gst-plugins-good/commit/?id=4cd9255f0a8a9e15d81561f00f02d275b5095f70

Author: Oleksij Rempel (Alexey Fisher) <bug-track at fisher-privat.net>
Date:   Thu Mar  1 14:15:29 2012 +0100

v4l2src: fix v4l2_munmap() for compressed formats

Make sure we always call munmap() with the same size we called mmap()
with before.

Current v4l2src uses the same structure for VIDIOC_QUERYBUF, VIDIOC_QBUF
and v4l2_munmap calls. The problem is that the video buffer size (length)
may vary for compressed or emulated bufs. VIDIOC_QBUF will change it if
we pass the pointer of a v4l2_buffer. This is why we should avoid using
same variable for mmap and video buffers.

https://bugzilla.gnome.org/show_bug.cgi?id=671126

---

 sys/v4l2/gstv4l2bufferpool.c |    5 +++--
 sys/v4l2/gstv4l2bufferpool.h |    3 +++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/sys/v4l2/gstv4l2bufferpool.c b/sys/v4l2/gstv4l2bufferpool.c
index b81c6a4..51419ff 100644
--- a/sys/v4l2/gstv4l2bufferpool.c
+++ b/sys/v4l2/gstv4l2bufferpool.c
@@ -106,9 +106,9 @@ gst_v4l2_buffer_finalize (GstV4l2Buffer * buffer)
   if (!resuscitated) {
     GST_LOG_OBJECT (pool->v4l2elem,
         "buffer %p (data %p, len %u) not recovered, unmapping",
-        buffer, GST_BUFFER_DATA (buffer), buffer->vbuffer.length);
+        buffer, GST_BUFFER_DATA (buffer), buffer->mmap_length);
     gst_mini_object_unref (GST_MINI_OBJECT (pool));
-    v4l2_munmap ((void *) GST_BUFFER_DATA (buffer), buffer->vbuffer.length);
+    v4l2_munmap ((void *) GST_BUFFER_DATA (buffer), buffer->mmap_length);
 
     GST_MINI_OBJECT_CLASS (v4l2buffer_parent_class)->finalize (GST_MINI_OBJECT
         (buffer));
@@ -183,6 +183,7 @@ gst_v4l2_buffer_new (GstV4l2BufferPool * pool, guint index, GstCaps * caps)
   GST_LOG_OBJECT (pool->v4l2elem, "  length:    %u", ret->vbuffer.length);
   GST_LOG_OBJECT (pool->v4l2elem, "  input:     %u", ret->vbuffer.input);
 
+  ret->mmap_length = ret->vbuffer.length;
   data = (guint8 *) v4l2_mmap (0, ret->vbuffer.length,
       PROT_READ | PROT_WRITE, MAP_SHARED, pool->video_fd,
       ret->vbuffer.m.offset);
diff --git a/sys/v4l2/gstv4l2bufferpool.h b/sys/v4l2/gstv4l2bufferpool.h
index caad9ac..36ea323 100644
--- a/sys/v4l2/gstv4l2bufferpool.h
+++ b/sys/v4l2/gstv4l2bufferpool.h
@@ -70,6 +70,9 @@ struct _GstV4l2Buffer {
   GstBuffer   buffer;
 
   struct v4l2_buffer vbuffer;
+  /* warning: the size of mmap buffer and
+   * the actual frame-buffer can be different. */
+  size_t mmap_length;
 
   /* FIXME: have GstV4l2Src* instead, as this has GstV4l2BufferPool* */
   /* FIXME: do we really want to fix this if GstV4l2Buffer/Pool is shared