Re: working around a Marvell wifi SDIO bug

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On Sat, Dec 4, 2010 at 6:22 PM, Daniel Drake <dsd@xxxxxxxxxx> wrote:
> In this case we are not changing current or voltage, we are just
> asserting a specific signal to the card. So its messy from the start
> (I'd have to invent a list of supported voltages or something).

This is exactly what we do today with the 12xx - we just need to
assert a digital signal, which by no means power the device (the
voltage value we provide isn't really fed from the gpio signal).

Your case might be slightly different, but still I think it's worth
looking into this approach first.

> Another option would be just to hack this into the kernel. Inside
> mmc_power_up we'd add something like the following:
>
> #ifdef CONFIG_OLPC
> if (machine_is_olpc())
>   olpc_reset_gpio_fixup(host);
> #endif

Please don't.

Core code should not contain such machine-specific details (imagine
how it would look when other boards will start adding this 8686
tweak...).

> Another cleaner option (but perhaps OTT for just 1 user?) would be to
> add a notifier chain that is called at this point.

That would obviously work but as you and Nicolas mentioned it's an
overkill: we don't really need random users to plug into this hook,
and using notifiers will just make the code less readable and harder
to debug, so it's better to try to find a solution that fits.
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