Re: mmc: sdio: runtime PM and 8686 problems

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On Thu, Dec 1, 2011 at 5:28 AM, Joe Woodward <jw@xxxxxxxxxxxxxx> wrote:
> I've had a play with the nRESET line (as far as I can tell it is the only pin I have access to), and no joy.
>
> Also tried playing about a bit with the CMD sequence, again no joy.
>
> I'm not entirely sure of the CMD sequence. It seems we get:
>  - CMD52 (x2)
>  - CMD0
>  - CMD8 (fails)
>  - CMD5 (fails)
>
> In the "SDIO Simplified Specification Version 2.00" (https://www.sdcard.org/developers/overview/sdio/sdio_spec/Simplified_SDIO_Card_Spec.pdf) page 6 it
> seems only a CMD52 should be required to "Re-init IO". Previous thread posts state CMD5 (x2) are required by the 8686, but why CMD0/CMD8?
>
> Incidentally errors only occur after the CMD0, but before the first error we get (i.e. a change of cs from 1 to 0):
> "mmc1: clock 400000Hz busmode 2 powermode 2 cs 0 Vdd 20 width 0 timing 0".

Can you see how this compares with older working kernels?

Some more things to try:
there are some delays in mmc_power_off - try increasing them to 1000.


mmc_sdio_power_restore does:
sdio_reset (cmd52)
mmc_go_idle (cmd0)
mmc_send_if_cond (cmd8)
mmc_send_io_op_cond (cmd52)

These are the commands you have been looking at from the angle of the logs.

Try sprinkling in a load of msleep(500) delays before and inbetween
those commands. And if you suspect some of them are not necessary
trying removing them, etc.

Non-scientific but this is how we have got things working so far :)

Thanks,
Daniel
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