# Re: \[PATCH 05/28\] media/v4l2: remove V4L2-FLAG-MEMORY-NON-CONSISTENT

- From: Christoph Hellwig \<hch@lst.de\>
- Date: 2020-08-19 13:55:09 
- List: netdev
- Page: https://ratatoskr.run/netdev/2020/08/6074145
- Thread: https://ratatoskr.run/alsa-devel/2020/08/6073543/t.md

```text
On Wed, Aug 19, 2020 at 01:16:51PM +0200, Tomasz Figa wrote:
> Hi Christoph,
> 
> On Wed, Aug 19, 2020 at 8:56 AM Christoph Hellwig [ref] wrote:
> >
> > The V4L2-FLAG-MEMORY-NON-CONSISTENT flag is entirely unused,
> 
> Could you explain what makes you think it's unused? It's a feature of
> the UAPI generally supported by the videobuf2 framework and relied on
> by Chromium OS to get any kind of reasonable performance when
> accessing V4L2 buffers in the userspace.

Because it doesn't do anything except on PARISC and non-coherent MIPS,
so by definition it isn't used by any of these media drivers.
```