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From: kishon@ti•com (Kishon Vijay Abraham I)
To: linux-arm-kernel@lists•infradead.org
Subject: Nokia N900: u-SD card in v4.2+
Date: Mon, 11 Jan 2016 14:10:23 +0530	[thread overview]
Message-ID: <56936A77.9070803@ti.com> (raw)
In-Reply-To: <201601092344.44641@pali>

Hi,

On Sunday 10 January 2016 04:14 AM, Pali Roh?r wrote:
> On Thursday 07 January 2016 12:34:09 Pavel Machek wrote:
>> Hi!
>>
>>> On Thursday 07 January 2016 02:16 AM, Pavel Machek wrote:
>>>> Hi!
>>>>
>>>> In v4.1, both internal MMC and u-SD cards work ok.
>>>>
>>>> In v4.2, only the internal MMC is detected. In v4.3, not even
>>>> internal MMC works. In v4.4, only the internal MMC is detected.
>>>>
>>>> Does it work for you? Any patches?
>>>
>>> I don't have Nokia N900 to check this, but can you share your
>>> config and kernel logs? Check if CONFIG_REGULATOR_PBIAS is present
>>> in your config. CONFIG_REGULATOR_PBIAS is now mandatory for all
>>> omap3+ SoCs to work.
>>
>> I enabled CONFIG_REGULATOR_PBIAS and both MMCs now work.
>>
>> I wonder if we should add some selects, so that users updating from
>> old kernels don't break their system?
> 
> Please add these selects. I had CONFIG_REGULATOR_PBIAS disabled too, 
> because I just updated defconfig from older kernel version.

'select' is generally not recommended since it selects a config without
caring for the dependency. With adding 'depends on', MMC won't be enabled and
will end up in the same problem.

Tony has already added a Documentation noting that CONFIG_REGULATOR_PBIAS
should be enabled for MMCs to work.
commit d8e1f5ed11a39a68da00f05000466c4f6db4456e
Author: Tony Lindgren <tony@atomide•com>
Date:   Mon Oct 12 16:19:54 2015 -0700

    Documentation: ARM: List new omap MMC requirements

Maybe we should also make the error message a little more verbose to tell the
user that CONFIG_REGULATOR_PBIAS be selected?

Thanks
Kishon

  reply	other threads:[~2016-01-11  8:40 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-06 20:46 Nokia N900: u-SD card in v4.2+ Pavel Machek
2016-01-07  5:40 ` Kishon Vijay Abraham I
2016-01-07 11:34   ` Pavel Machek
2016-01-09 22:44     ` Pali Rohár
2016-01-11  8:40       ` Kishon Vijay Abraham I [this message]
2016-01-13 19:12         ` Pavel Machek
2016-01-13 19:20           ` Tony Lindgren

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