On Tue, Sep 1, 2020 at 1:06 PM Christoph Hellwig wrote:
>
> On Thu, Aug 20, 2020 at 07:33:48PM +0200, Tomasz Figa wrote:
> > > It wasn't meant to be too insulting, but I found this out when trying
> > > to figure out how to just disable it. But it also ends up using
> > > the actual dma attr flag
On Thu, Aug 20, 2020 at 07:33:48PM +0200, Tomasz Figa wrote:
> > It wasn't meant to be too insulting, but I found this out when trying
> > to figure out how to just disable it. But it also ends up using
> > the actual dma attr flags for it's own consistency checks, so just
> > not setting the flag
On Thu, Aug 20, 2020 at 6:52 PM Christoph Hellwig wrote:
>
> On Thu, Aug 20, 2020 at 12:24:31PM +0200, Tomasz Figa wrote:
> > > Of course this still uses the scatterlist structure with its annoying
> > > mix of input and output parametes, so I'd rather not expose it as
> > > an official API at the
On Thu, Aug 20, 2020 at 6:54 PM Christoph Hellwig wrote:
>
> On Thu, Aug 20, 2020 at 12:05:29PM +0200, Tomasz Figa wrote:
> > The UAPI and V4L2/videobuf2 changes are in good shape and the only
> > wrong part is the use of DMA API, which was based on an earlier email
> > guidance anyway, and a chan
On Thu, Aug 20, 2020 at 12:05:29PM +0200, Tomasz Figa wrote:
> The UAPI and V4L2/videobuf2 changes are in good shape and the only
> wrong part is the use of DMA API, which was based on an earlier email
> guidance anyway, and a change to the synchronization part . I find
> conclusions like the above
On Thu, Aug 20, 2020 at 12:24:31PM +0200, Tomasz Figa wrote:
> > Of course this still uses the scatterlist structure with its annoying
> > mix of input and output parametes, so I'd rather not expose it as
> > an official API at the DMA layer.
>
> The problem with the above open coded approach is t
On Thu, Aug 20, 2020 at 12:09:34PM +0200, Tomasz Figa wrote:
> > I'm happy to Cc and active participant in the discussion. I'm not
> > going to add all reviewers because even with the trimmed CC list
> > I'm already hitting the number of receipients limit on various lists.
>
> Fair enough.
>
> W
On Thu, Aug 20, 2020 at 7:02 AM Christoph Hellwig wrote:
>
> On Wed, Aug 19, 2020 at 03:07:04PM +0100, Robin Murphy wrote:
> >> FWIW, I asked back in time what the plan is for non-coherent
> >> allocations and it seemed like DMA_ATTR_NON_CONSISTENT and
> >> dma_sync_*() was supposed to be the righ
On Thu, Aug 20, 2020 at 6:45 AM Christoph Hellwig wrote:
>
> On Wed, Aug 19, 2020 at 04:11:52PM +0200, Tomasz Figa wrote:
> > > > By the way, as a videobuf2 reviewer, I'd appreciate being CC'd on any
> > > > series related to the subsystem-facing DMA API changes, since
> > > > videobuf2 is one of
On Thu, Aug 20, 2020 at 7:20 AM Christoph Hellwig wrote:
>
> On Thu, Aug 20, 2020 at 06:43:47AM +0200, Christoph Hellwig wrote:
> > On Wed, Aug 19, 2020 at 03:57:53PM +0200, Tomasz Figa wrote:
> > > > > Could you explain what makes you think it's unused? It's a feature of
> > > > > the UAPI genera
On Thu, Aug 20, 2020 at 06:43:47AM +0200, Christoph Hellwig wrote:
> On Wed, Aug 19, 2020 at 03:57:53PM +0200, Tomasz Figa wrote:
> > > > 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 Ch
On Wed, Aug 19, 2020 at 03:07:04PM +0100, Robin Murphy wrote:
>> FWIW, I asked back in time what the plan is for non-coherent
>> allocations and it seemed like DMA_ATTR_NON_CONSISTENT and
>> dma_sync_*() was supposed to be the right thing to go with. [2] The
>> same thread also explains why dma_all
On Wed, Aug 19, 2020 at 04:22:29PM +0200, Tomasz Figa wrote:
> > > FWIW, I asked back in time what the plan is for non-coherent
> > > allocations and it seemed like DMA_ATTR_NON_CONSISTENT and
> > > dma_sync_*() was supposed to be the right thing to go with. [2] The
> > > same thread also explains
On Wed, Aug 19, 2020 at 04:11:52PM +0200, Tomasz Figa wrote:
> > > By the way, as a videobuf2 reviewer, I'd appreciate being CC'd on any
> > > series related to the subsystem-facing DMA API changes, since
> > > videobuf2 is one of the biggest users of it.
> >
> > The cc list is too long - I cc list
On Wed, Aug 19, 2020 at 03:57:53PM +0200, Tomasz Figa wrote:
> > > 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 V4
On Wed, Aug 19, 2020 at 4:07 PM Robin Murphy wrote:
>
> On 2020-08-19 13:49, Tomasz Figa wrote:
> > On Wed, Aug 19, 2020 at 1:51 PM Robin Murphy wrote:
> >>
> >> Hi Tomasz,
> >>
> >> On 2020-08-19 12:16, Tomasz Figa wrote:
> >>> Hi Christoph,
> >>>
> >>> On Wed, Aug 19, 2020 at 8:56 AM Christoph
On Wed, Aug 19, 2020 at 3:57 PM Christoph Hellwig wrote:
>
> On Wed, Aug 19, 2020 at 02:49:01PM +0200, Tomasz Figa wrote:
> > With the default config it doesn't, but with
> > CONFIG_DMA_NONCOHERENT_CACHE_SYNC enabled it makes dma_pgprot() keep
> > the pgprot value as is, without enforcing coherenc
On 2020-08-19 13:49, Tomasz Figa wrote:
On Wed, Aug 19, 2020 at 1:51 PM Robin Murphy wrote:
Hi Tomasz,
On 2020-08-19 12:16, Tomasz Figa wrote:
Hi Christoph,
On Wed, Aug 19, 2020 at 8:56 AM Christoph Hellwig wrote:
The V4L2-FLAG-MEMORY-NON-CONSISTENT flag is entirely unused,
Could you e
On Wed, Aug 19, 2020 at 3:55 PM Christoph Hellwig wrote:
>
> 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 wrote:
> > >
> > > The V4L2-FLAG-MEMORY-NON-CONSISTENT flag is entirely unused,
> >
> > Could you e
On Wed, Aug 19, 2020 at 02:49:01PM +0200, Tomasz Figa wrote:
> With the default config it doesn't, but with
> CONFIG_DMA_NONCOHERENT_CACHE_SYNC enabled it makes dma_pgprot() keep
> the pgprot value as is, without enforcing coherence attributes.
Which isn't selected on arm64, and that is for a good
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 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 gene
On Wed, Aug 19, 2020 at 1:51 PM Robin Murphy wrote:
>
> Hi Tomasz,
>
> On 2020-08-19 12:16, Tomasz Figa wrote:
> > Hi Christoph,
> >
> > On Wed, Aug 19, 2020 at 8:56 AM Christoph Hellwig wrote:
> >>
> >> The V4L2-FLAG-MEMORY-NON-CONSISTENT flag is entirely unused,
> >
> > Could you explain what m
Hi Tomasz,
On 2020-08-19 12:16, Tomasz Figa wrote:
Hi Christoph,
On Wed, Aug 19, 2020 at 8:56 AM Christoph Hellwig 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 v
Hi Christoph,
On Wed, Aug 19, 2020 at 8:56 AM Christoph Hellwig 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 ge
The V4L2-FLAG-MEMORY-NON-CONSISTENT flag is entirely unused, and causes
weird gymanstics with the DMA_ATTR_NON_CONSISTENT flag, which is
unimplemented except on PARISC and some MIPS configs, and about to be
removed.
Signed-off-by: Christoph Hellwig
---
.../userspace-api/media/v4l/buffer.rst
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