[PATCH 6/7] [media] gspca: fix a v4l2-compliance failure during VIDIOC_REQBUFS

[Antonio Ospite <ao2@ao2.it>]

When calling VIDIOC_REQBUFS v4l2-compliance fails with this message:

  fail: v4l2-test-buffers.cpp(476): q.reqbufs(node, 1)
  test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: FAIL

By looking at the v4l2-compliance code the failure happens when trying
to request V4L2_MEMORY_USERPTR buffers without freeing explicitly the
previously allocated V4L2_MEMORY_MMAP buffers.

This would suggest that when changing the memory field in struct
v4l2_requestbuffers the driver is supposed to free automatically any
previous allocated buffers, and looking for inspiration at the code in
drivers/media/v4l2-core/videobuf2-core.c::vb2_core_reqbufs() seems to
confirm this interpretation; however gspca is just returning -EBUSY in
this case.

Removing the special handling for the case of a different memory value
fixes the compliance failure.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
---

This should be safe, but I'd really like a comment from someone with a more
global knowledge of v4l2.

If my interpretation about how drivers should behave when the value of the
memory field changes is correct, I could send also a documentation update for
Documentation/DocBook/media/v4l/vidioc-reqbufs.xml

Just let me know.

Thanks,
   Antonio


 drivers/media/usb/gspca/gspca.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/media/usb/gspca/gspca.c b/drivers/media/usb/gspca/gspca.c
index 84b0d6a..915b6c7 100644
--- a/drivers/media/usb/gspca/gspca.c
+++ b/drivers/media/usb/gspca/gspca.c
@@ -1402,13 +1402,6 @@ static int vidioc_reqbufs(struct file *file, void *priv,
 	if (mutex_lock_interruptible(&gspca_dev->queue_lock))
 		return -ERESTARTSYS;
 
-	if (gspca_dev->memory != GSPCA_MEMORY_NO
-	    && gspca_dev->memory != GSPCA_MEMORY_READ
-	    && gspca_dev->memory != rb->memory) {
-		ret = -EBUSY;
-		goto out;
-	}
-
 	/* only one file may do the capture */
 	if (gspca_dev->capt_file != NULL
 	    && gspca_dev->capt_file != file) {
-- 
2.7.0