MMC runtime PM patches break libertas probe

Mike Rapoport mike at compulab.co.il
Wed Nov 17 01:46:44 EST 2010


On 11/16/10 16:49, Ohad Ben-Cohen wrote:
> On Tue, Nov 16, 2010 at 4:29 PM, Daniel Drake <dsd at laptop.org> wrote:
>> On 16 November 2010 13:22, Ohad Ben-Cohen <ohad at wizery.com> wrote:
>>> Just to update the list, the problem with the XO-1.5 was because the
>>> sd8686 has an external reset gpio line which is currently being
>>> manipulated manually by an out-of-tree kernel patch:
>>>
>>> http://dev.laptop.org/git/olpc-2.6/commit/?h=olpc-2.6.35&id=e9bee721fb0cc303286d1fe5df4930ce79b0b1e0
>>>
>>> ... which makes me wonder whether we really want to take that
>>> MMC_CAP_RUNTIME_PM road. I'm not sure anymore.
>>
>> OLPC is not the only user of the sd8686.
>> Every other user will face the same problem.
>>
>> Other users may not have the luxury of having a GPIO hooked up to the
>> reset line.
> 
> Agree; those users will need a MMC_CAP_RUNTIME_PM (or maybe call it
> with the capability it really stands for which is something like
> MMC_CAP_POWER_OFF_CARD).
> 
> But I want to be positively sure we have such users (or is it that obvious?).
> 
> How is the sd8686's reset line manipulated on other platforms ? Or is
> the sd8686 usually just kept powered on after boot ?

On our platforms we just keep it powered on after boot with the reset line held
high. (e.g. arch/arm/mach-pxa/cm-x300.c, arch/arm/mach-omap/board-cm-t35.c). We
don't bother much for power savings, though.

> I'm looping in libertas-dev.
> 
> Thanks,
> Ohad.
> 
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-- 
Sincerely yours,
Mike.



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