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
Also in:
alsa-devel, linux-arm-kernel, linux-doc, linux-iommu, linux-media, linux-mips, linux-mm, linux-nvme, linux-samsung-soc, linux-scsi, lkml, nouveau
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 [off-list ref] wrote:quoted
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.