Hi Thomas, On Friday 04 April 2014 20:01:33 Scheuermann, Mail wrote: > Hi Laurent, > > I've done the following: > > echo 3 >/sys/module/videobuf2_core/parameters/debug > > and found in /var/log/kern.log after starting my program: > > [239432.535077] vb2: Buffer 0, plane 0 offset 0x00000000 > [239432.535080] vb2: Buffer 1, plane 0 offset 0x001c2000 > [239432.535082] vb2: Buffer 2, plane 0 offset 0x00384000 > [239432.535083] vb2: Allocated 3 buffers, 1 plane(s) each > [239432.535085] vb2: qbuf: userspace address for plane 0 changed, > reacquiring memory > [239432.535087] vb2: qbuf: failed acquiring userspace memory for plane 0 This confirms everything is working properly up to the point where videobuf2- vmalloc fails to acquire the user pointer memory. The problem comes from vb2_vmalloc_get_userptr() in drivers/media/v4l2-core/videobuf2-vmalloc.c. Unfortunately that function lacks debugging. Are you familiar enough with kernel programming to add printk statements there and see where it fails ? > [239432.535088] vb2: qbuf: buffer preparation failed: -22 > [239432.535128] vb2: streamoff: not streaming -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
