Re: MMC runtime PM patches break libertas probe

[Ohad Ben-Cohen <ohad@wizery.com>]

Hi Zhangfei,

On Fri, Jun 10, 2011 at 5:02 AM, zhangfei gao <zhangfei.gao@gmail.com> wrote:
> Here is answer got from the sd8686 maintainer.
>
> For 8686, the SDIO state machine can only handle init sequence (CMD5,
> 5, 3, 7) from host once. If host sends another init sequence, it will
> not be able to handle CMD5 and causes the SDIO block to hang. Chips
> that are newer than 8686 will be able to handle multiple init sequence
> from host.

Thanks for the reply !

> So yes, for 8686, an IO reset is needed before host can send a new set
> of init sequence.

But if we're powering down and up the device first, then the init
sequence is considered the first one, and then we don't need an IO
reset, right ? That was what we wondered about.

Thanks,
Ohad.