Hi,
On 14-03-16 16:02, Antonio Ospite wrote:
On Thu, 10 Mar 2016 15:54:37 +0100
Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
Hi,
On 09-03-16 17:03, Antonio Ospite wrote:
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@xxxxxx>
---
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;
- }
-
reqbufs is used internally and this change will allow changing
gspca_dev->memory from USERPTR / MMAP to GSPCA_MEMORY_READ
please replace this check with a check to only allow
rb->memory to be GSPCA_MEMORY_READ when coming from GSPCA_MEMORY_NO
or GSPCA_MEMORY_READ
OK, thanks, I'll take a look again later this week.
In the meantime, if patches from 1 to 5 are OK, can we have them merged
so I will just resubmit the last two in the set?
Not sure when I'll have time to do this, I would prefer to also take
v2 of patch 6 and 7 while at it. But I agree that there is no need
to pick op patches 1 - 5. I'll pick them up from patchwork when I've
time.
Regards,
Hans
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