Re: [PATCH] i2c-s3c2410: Add stub runtime power management

[Mark Brown <broonie@opensource.wolfsonmicro.com>]

On Sun, Jan 22, 2012 at 06:48:36PM +0100, Sylwester Nawrocki wrote:
> On 01/22/2012 06:27 PM, Bill Gatliff wrote:

> > I for one would rather see in-kernel drivers that require it, and then

> In fact we have to deal with the opposite now, as some existing drivers
> have been used for multiple generations of SoC, where almost unchanged
> device IPs are deployed. Those drivers were originally written for the
> simplest SoCs.

TBH I think most of the devices for which people are running these days
will be able to get some win from the system wide stuff - the WFI modes
aren't exactly the latest thing in hardware terms, it's just been a long
road to getting them supported.  Infrastructure like Mark's PM QoS work
and Raphael's PM domains work has really helped a lot here.

> > patches in mailing lists that show how to un-require it.  Make it more
> > painful to avoid PM_RUNTIME, and less painful to use it.

> Yeah, makes a lot of sense. With new code there is no issue, only the code
> with long history is sort of troublesome.

It's mostly a transition management issue I think.  When I repost I'll
add an additional patch on top which moves the clock gating into the
runtime PM callbacks, that way the decision on that doesn't block the
system wide work.