Re: V4L2_BUF_FLAG_NO_CACHE_*

Hans Verkuil
2013-10-07T14:31:24Z

On 10/07/2013 01:31 PM, Krzysztof Hałasa wrote:
> Hi,
>
> found them looking for my V4L2 + mmap + MIPS solution... Is the
> following intentional? Some out-of-tree code maybe?

No, this is intentional. Too bad this was never actually implemented in any
driver. Marek, Pawel, wouldn't it be possible to add support for these flags
in vb2? That seems the right place for this.

Regards,

Hans

>
> $ grep V4L2_BUF_FLAG_NO_CACHE_ * -r
>
> Documentation/DocBook/media/v4l/io.xml: <entry><constant>V4L2_BUF_FLAG_NO_CACHE_INVALIDATE</constant></entry>
> Documentation/DocBook/media/v4l/io.xml: <entry><constant>V4L2_BUF_FLAG_NO_CACHE_CLEAN</constant></entry>
> Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml:<constant>V4L2_BUF_FLAG_NO_CACHE_INVALIDATE</constant> and
> Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml:<constant>V4L2_BUF_FLAG_NO_CACHE_CLEAN</constant> flags to skip the respective
> include/uapi/linux/videodev2.h:#define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE 0x0800
> include/uapi/linux/videodev2.h:#define V4L2_BUF_FLAG_NO_CACHE_CLEAN 0x1000
>