Re: [Update][PATCH 8/8] ARM / shmobile: Support for I/O power domains for SH7372 (v6)

Paul Mundt
2011-06-21T12:47:43Z

On Tue, Jun 21, 2011 at 01:57:08PM +0200, Rafael J. Wysocki wrote:
> On Tuesday, June 21, 2011, Rafael J. Wysocki wrote:
> > On Monday, June 20, 2011, Paul Mundt wrote:
> > > Given that these functions can return errors, it's probably more prudent
> > > to implement some timeout logic on top of the busy loop. Hardware does
> > > get stuck, after all.
> >
> > Yes, it does, but we don't really know what timeout value to use in there.
> >
> > In fact, failures of pd_power_down() don't really matter (at worst the power
> > domain won't be powered off really) and pd_power_up() should only return error
> > code if the error is known to be unrecoverable.
> >
> > So, what about this: repeat certain number of times (I verified that it took
> > several iterations of the loop until the new value settled on my hardware)
> > and then return from pd_power_down() or go to sleep for a short time and repeat
> > in pd_power_up()?
>
> Having discussed that with Magnus I changed pd_power_down() to use a timeout.
> Specifically, it will bail out if the state doesn't change after approximately
> 1 ms.
>
Looks good to me, thanks for fixing it up.

Acked-by: Paul Mundt <lethal@linux-sh.org>