On Tue, 14 Dec 2010, Mark Brown wrote: > On Tue, Dec 14, 2010 at 11:16:45AM -0500, Alan Stern wrote: > > > I'm not familiar with the details of how the i2c subsystem works. But > > in general, the subsystem code should call pm_runtime_set_active() > > for every device before registering it. Then if a driver doesn't use > > any runtime-PM functions, pm_runtime_suspended() will return false. > > Hrm, if that's the case then we also need to update at least the > platform and SPI buses. Though looking at the documentation this is > going to get a bit interesting as there's a requirement that the parent > has runtime PM enabled on it... The parent can either be set to the active state or set to ignore its children. The parent does not have to be enabled for runtime PM. > It's certainly not terribly apparent > from the documentation. What part isn't clear from the documentation? I think the description of pm_runtime_set_active() in Documentation/power/runtime_pm.txt is pretty straightforward. > It'd be really helpful if it were clearer what noop buses like this were > supposed to do to get runtime PM working. I'm a little confused. When you say this is a "noop" bus, do you mean that it can't do any power management? If so, why does it need to get runtime PM working? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
