Re: 900af0d breaks some embedded suspend/resume

Rafael J. Wysocki
2009-04-18T22:45:30Z

On Saturday 18 April 2009, Linus Torvalds wrote:
>
> On Sat, 18 Apr 2009, Russell King wrote:
> >
> > What I need to be able to do is to suspend most devices on the host side
> > which may involve talking to a separate microcontroller via I2C to shut
> > down power to peripherals.
>
> I suspect that for cases like this, the simplest thing to do is to just
> add a marker for "don't mess with my power management, I'm doing
> everything through sysdev" for the specified devices.

In this particular case, if sysdev was used, there would be no problem, but the
platform uses a platform device to suspend-resume the i2c controller.
In principle we could convert it to use a sysdev, but that would be more
difficult than the last patch I sent IMO (at least to me).

Also, apparently it is not the only platform doing it.

> Then those i2c controllers (and perhaps some PCI bridges etc) can just set
> that bit, and the device would basically turn invisible as far as the PM
> layer is concerned.
>
> Not that different from the IRQF_TIMER bit for timer interrupts.

I generally agree and a patch to implemet such a flag has been submitted
recently.

Thanks,
Rafael