From: Wolfram Sang <wsa@the-dreams.de>
To: Stephen Boyd <swboyd@chromium.org>
Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
linux-arm-msm@vger.kernel.org,
Karthikeyan Ramasubramanian <kramasub@codeaurora.org>,
Sagar Dharia <sdharia@codeaurora.org>,
Girish Mahadevan <girishm@codeaurora.org>
Subject: Re: [PATCH] i2c: i2c-qcom-geni: Properly handle DMA safe buffers
Date: Wed, 19 Sep 2018 00:16:46 +0200 [thread overview]
Message-ID: <20180918221646.GA970@kunai> (raw)
In-Reply-To: <20180918194126.138455-1-swboyd@chromium.org>
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> This fixes a problem where the kernel oopses cleaning pages for a buffer
> that's mapped into the vmalloc space. The pages are returned from
> request_firmware() and passed down directly to the i2c master to write
> to the i2c touchscreen device. Mapping vmalloc buffers with
> dma_map_single() won't work reliably, causing an oops like below:
Exactly the reason why I implemented I2C_M_DMA_SAFE. Did you also notice
the helper i2c_get_dma_safe_msg_buf() which you maybe could use for
len > 32?
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next prev parent reply other threads:[~2018-09-18 22:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-18 19:41 [PATCH] i2c: i2c-qcom-geni: Properly handle DMA safe buffers Stephen Boyd
2018-09-18 22:16 ` Wolfram Sang [this message]
2018-09-19 18:25 ` Stephen Boyd
2018-09-19 20:45 ` Wolfram Sang
2018-09-20 5:14 ` Stephen Boyd
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