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From:   Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Date:   Mon, 12 Nov 2018 18:04:06 -0300
Message-ID: <CAAEAJfBUEj+4RnHmK9RvOv7cghQNr0xNqr5GdVTG+V88+Kzi8Q@mail.gmail.com>
Subject: Re: Bug report: MIPS CI20/jz4740-mmc DMA and PREEMPT_NONE
To:     aaro.koskinen@iki.fi
Cc:     Mathieu Malaterre <malat@debian.org>,
        Linux-MIPS <linux-mips@linux-mips.org>,
        linux-mmc@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Ezequiel Garcia <ezequiel@collabora.co.uk>
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On Wed, 17 Oct 2018 at 16:50, Aaro Koskinen <aaro.koskinen@iki.fi> wrote:
>
> Hi,
>
> On Wed, Oct 17, 2018 at 03:38:07PM +0200, Mathieu Malaterre wrote:
> > Since CONFIG_PREEMPT has been 'y' since at least commit 0752f92934292
> > could you confirm that the original mmc driver (kernel from imgtech
> > people) did work ok with PREEMPT_NONE (sorry I did not do my homework)
> > ?
>
> Sorry, cannot confirm or test that. I have only used the mainline kernel
> on this board, since v4.5 or so with my own custom config which has
> been PREEMPT_NONE until now.
>

Aaro,

I spent some time today investigating this issue. I think this driver
has a broken pre-request/post-request implementation.

Will post some patches soon.

Thanks for the report,
--=20
Ezequiel Garc=C3=ADa, VanguardiaSur
www.vanguardiasur.com.ar