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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Tue, 10 Nov 2020 10:33:05 +0100
Message-ID: <CANiDSCsBUBV1WA2To9x26Uhc5SU-4xuh3m4wUwXBcGwA6n8now@mail.gmail.com>
Subject: Re: [PATCH 8/8] WIP: add a dma_alloc_contiguous API
To:     Christoph Hellwig <hch@lst.de>
Cc:     Tomasz Figa <tfiga@chromium.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>, Joerg
        Roedel <joro@8bytes.org>," <iommu@lists.linux-foundation.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>
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Hi Christoph

On Tue, Nov 10, 2020 at 10:25 AM Christoph Hellwig <hch@lst.de> wrote:
>
> On Mon, Nov 09, 2020 at 03:53:55PM +0100, Ricardo Ribalda wrote:
> > Hi Christoph
> >
> > I have started now to give a try to your patchset. Sorry for the delay.
> >
> > For uvc I have prepared this patch:
> > https://github.com/ribalda/linux/commit/9094fe223fe38f8c8ff21366d893b43cbbdf0113
> >
> > I have tested successfully in a x86_64 noteboot..., yes I know there
> > is no change for that platform :).
> > I am trying to get hold of an arm device that can run the latest
> > kernel from upstream.
> >
> > On the meanwhile if you could take a look to the patch to verify that
> > this the way that you expect the drivers to use your api I would
> > appreciate it
>
> This looks pretty reaosnable.
>

Great

Also FYI, I managed to boot an ARM device with that tree. But I could
not test the uvc driver (it was a remote device with no usb device
attached)

Hopefully I will be able to test it for real this week.

Any suggestions for how to measure performance difference?

Thanks!

> Note that ifdef  CONFIG_DMA_NONCOHERENT in the old code doesn't actually
> work, as that option is an internal thing just for mips and sh..


-- 
Ricardo Ribalda