Re: [PATCH v4] mmc: Make ID freq configurable

From: Michal Miroslaw
Date: Fri Dec 03 2010 - 01:56:20 EST


On Thu, Dec 02, 2010 at 09:05:54PM -0800, stummala@xxxxxxxxxxxxxx wrote:
> Hi Michal,
[...]
> >> > In case of SDIO error, mmc_power_off() is getting called as part of
> >> > mmc_detach_bus(). Shouldn't we power up the host before checking for
> >> > SDMEM? Any comments?
> >> I think you should ask Michal Miroslaw, as he wrote the patch for the
> >> SD-combo (IO + mem)*
> >>
> >> But yes, in case of a failure, mmc_attach_sdio() will call
> >> mmc_detach_bus()
> >> which in turn will call mmc_power_off()
> >>
> >> And so it should be mmc_power_up() again before trying to detect SD
> >> memory.
> > Yes, you are right! This explains some things...
> >
> > Please try attached patch. (Not tested, but obvious enough.)
> I was looking at the code and figured out this issue. I don't have any
> SD-combo card to verify your patch.

You shouldn't be able to use this code path with normal SD-combo cards.
This is relevant if you have a card that responds to CMD5 but then fails
SDIO part initialization in some circumstances (i.e. time-outs).

Best Regards,
Michał Mirosław
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