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

On Tue, Jun 21, 2011 at 01:57:08PM +0200, Rafael J. Wysocki wrote:

On Tuesday, June 21, 2011, Rafael J. Wysocki wrote:

quoted

On Monday, June 20, 2011, Paul Mundt wrote:

quoted

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 <redacted>