Re: MMC runtime PM patches break libertas probe

[Daniel Drake <dsd@laptop.org>]

On 7 November 2010 10:42, Ohad Ben-Cohen <ohad@wizery.com> wrote:
> Good. Did it also solve the 1st issue you had ?

Yes.

>> But, what you point out is quite interesting.
>> We currently have a (not-yet-upstream) rfkill driver for the XO-1.5,
>> which we also put in place for power saving reasons.
>
> Can you please elaborate ? What power saving ? How do you exactly plan
> to use it ? Do you plan to power off the card without taking the wlan
> interface down first ?

If you take the interface down, the card is still powered up in some
way. We were looking for a way to cut as much power as possible.
It can be used by the "rfkill block wifi" command, and theres a
checkbox available in the sugar UI which calls that.

> Chris and I briefly discussed this in LPC, and he mentioned that you
> might have an external power source to that card, that is not
> controlled by the mmc regulator, and which you disable/enable from
> user space just before suspending the host ?

Not sure what he's referring to there. Perhaps he can clarify.

When I asked the hardware guy he said it was entirely controlled by
the normal SD power pin, but a full card reset will be needed after
cycling the power.

Daniel