From: Christoph Hellwig <hch@infradead.org>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: "Matwey V. Kornilov" <matwey@sai.msu.ru>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
matwey.kornilov@gmail.com, tfiga@chromium.org,
stern@rowland.harvard.edu, ezequiel@collabora.com,
hdegoede@redhat.com, hverkuil@xs4all.nl, mchehab@kernel.org,
rostedt@goodmis.org, mingo@redhat.com, isely@pobox.com,
bhumirks@gmail.com, colin.king@canonical.com,
kieran.bingham@ideasonboard.com, keiichiw@chromium.org,
Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH v5 2/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer
Date: Fri, 7 Dec 2018 07:25:02 -0800 [thread overview]
Message-ID: <20181207152502.GA30455@infradead.org> (raw)
In-Reply-To: <2213616.rQm4DhIJ7U@avalon>
Folks, can you take a look at this tree and see if this is useful
for USB:
http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-noncoherent-allocator
The idea is that you use dma_alloc_attrs with the DMA_ATTR_NON_CONSISTENT
now that I've made sure it is avaiable everywhere [1], and we can use
dma_sync_single_* on it.
The only special case USB will need are the HCD_LOCAL_MEM devices, for
which we must use dma_alloc_coherent (or dma_alloc_attrs without
DMA_ATTR_NON_CONSISTENT) and must skip the dma_sync_single_* calls,
so we'll probably need USB subsystem wrappers for those calls.
[1] except powerpc in this tree - I have another series to make powerpc
use the generic dma noncoherent code, which would cover it.
next prev parent reply other threads:[~2018-12-07 15:25 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 17:06 [PATCH v5 0/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer Matwey V. Kornilov
2018-08-21 17:06 ` [PATCH v5 1/2] media: usb: pwc: Introduce TRACE_EVENTs for pwc_isoc_handler() Matwey V. Kornilov
2018-08-21 19:49 ` Steven Rostedt
2018-08-21 19:49 ` Steven Rostedt
2018-08-21 17:06 ` [PATCH v5 2/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer Matwey V. Kornilov
2018-08-28 7:17 ` Matwey V. Kornilov
2018-09-11 18:58 ` Matwey V. Kornilov
2018-09-19 16:12 ` Ezequiel Garcia
2018-10-10 21:13 ` Matwey V. Kornilov
2018-10-30 22:00 ` Laurent Pinchart
2018-10-31 5:38 ` Christoph Hellwig
2018-12-07 15:25 ` Christoph Hellwig [this message]
2018-12-12 8:57 ` Tomasz Figa
2018-12-12 9:09 ` Christoph Hellwig
2018-12-12 9:34 ` Tomasz Figa
2018-12-12 13:54 ` Christoph Hellwig
2018-12-13 3:13 ` Tomasz Figa
2018-12-13 14:03 ` Christoph Hellwig
2018-12-14 3:12 ` Tomasz Figa
2018-12-14 12:36 ` Christoph Hellwig
2018-12-18 7:22 ` Tomasz Figa
2018-12-18 7:38 ` Christoph Hellwig
2018-12-18 9:48 ` Tomasz Figa
2018-12-19 7:51 ` Christoph Hellwig
2018-12-19 8:18 ` Tomasz Figa
2018-12-19 14:51 ` Christoph Hellwig
2018-12-20 3:23 ` Tomasz Figa
2018-12-21 8:13 ` Christoph Hellwig
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