Hi Jonghun, On Tuesday 14 December 2010 11:51:17 Jonghun Han wrote: > Hi, > > Any comment for this ? > > In my opinion v4l2 spec is not accurate in this topic. > Because VIDIOC_REQBUFS describes count is only used in V4L2_MEMORY_MMAP as > below. > __u32 count The number of buffers requested or granted. This field is > only used when memory is set to V4L2_MEMORY_MMAP. > > But there is no comment in QBUF and DQBUF part about index. > So I am confused. If an index isn't needed, how to driver handle it ? The spec should be fixed. VIDIOC_REQBUFS needs to be called for USERPTR as well, and the buffer count is definitely used. > On Saturday, December 11, 2010 2:10 PM Jonghun Han wrote: > > > > I wonder that a index should be passed on the fly with the VIDIOC_QBUF > > ioctl in V4L2_MEMORY_USERPTR case. > > If it isn't needed, should driver return virtual address gotten from > > application on the fly with the VIDIOC_DQBUF ioctl ? VIDIOC_DQBUF is supposed to fill the v4l2_buffer structure with the index and the userspace virtual address (among other information). If it doesn't, it's a driver bug. -- 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
