Hi Laurent Pinchart, Thanks you for reply. It makes sense.
Best regards, Jonghun Han > -----Original Message----- > From: linux-media-ow...@vger.kernel.org [mailto:linux-media- > ow...@vger.kernel.org] On Behalf Of Laurent Pinchart > Sent: Tuesday, December 14, 2010 8:00 PM > To: Jonghun Han > Cc: linux-media@vger.kernel.org; 'Hans Verkuil'; mche...@redhat.com > Subject: Re: Should a index be passed on the fly with the VIDIOC_QBUF ioctl in > V4L2_MEMORY_USERPTR case ? > > 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 majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
