From: Chris Ball <cjb@laptop.org>
To: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
linux-mmc@vger.kernel.org, linux-sh@vger.kernel.org
Subject: Re: [PATCH v2] mmc: tmio: Don't access hardware registers after stopping clocks
Date: Wed, 20 Jun 2012 02:22:19 -0400 [thread overview]
Message-ID: <87fw9q4i5g.fsf@octavius.laptop.org> (raw)
In-Reply-To: <Pine.LNX.4.64.1206131527080.17854@axis700.grange> (Guennadi Liakhovetski's message of "Wed, 13 Jun 2012 15:27:35 +0200 (CEST)")
Hi,
On Wed, Jun 13 2012, Guennadi Liakhovetski wrote:
> On Tue, 12 Jun 2012, Laurent Pinchart wrote:
>
>> The tmio_mmc_set_ios() function configures the MMC power, clock and bus
>> width. When the mmc core requests the driver to power off the card, we
>> inform runtime PM, that the controller can be suspended. This can lead
>> to the MSTP clock being turned off.
>>
>> Writing to any 16-bit hardware registers with the MSTP clock off leads
>> to timeouts and errors being printed to the kernel log. This can occur
>> both when stopping the MMC clock and when configuring the bus width.
>>
>> To fix this, stop the MMC clock before calling put_runtime_pm(), and
>> skip bus width configuration when power is off.
>>
>> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Thanks, pushed to mmc-next for 3.6.
- Chris.
--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child
next prev parent reply other threads:[~2012-06-20 6:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-12 21:29 [PATCH v2] mmc: tmio: Don't access hardware registers after stopping clocks Laurent Pinchart
2012-06-13 1:17 ` Simon Horman
2012-06-13 7:42 ` Laurent Pinchart
2012-06-13 13:27 ` Guennadi Liakhovetski
2012-06-20 6:22 ` Chris Ball [this message]
2012-06-14 4:11 ` Kuninori Morimoto
2012-06-20 2:23 ` Simon Horman
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