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Date:   Mon, 30 Sep 2019 23:37:44 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Nicolas Boichat <drinkcat@chromium.org>
Cc:     Shik Chen <shik@chromium.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Tomasz Figa <tfiga@chromium.org>, notify@kernel.org,
        Keiichi Watanabe <keiichiw@chromium.org>,
        Ricky Liang <jcliang@chromium.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        lkml <linux-kernel@vger.kernel.org>,
        kieran.bingham@ideasonboard.com, Vlastimil Babka <vbabka@suse.cz>,
        Christoph Lameter <cl@linux.com>,
        Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH] media: uvcvideo: Use streaming DMA APIs to transfer
 buffers
Message-ID: <20191001063744.GA10402@infradead.org>
References: <20190802131226.123800-1-shik@chromium.org>
 <CANMq1KD3Pth7LNnVqxSesx3kSFte0eR5JqEBETv45s_9_YKWHw@mail.gmail.com>
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On Mon, Sep 30, 2019 at 01:23:10AM -0700, Christoph Hellwig wrote:
> And drivers really have no business looking at the dma mask.  I have
> a plan for dma_alloc_pages API that could replace that cruft, but
> until then please use GFP_KERNEL and let the dma subsystem bounce
> buffer if needed.

Can you try this series:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma_alloc_pages

and see if it does whay you need for usb?