On Saturday, June 11, 2011, Mark Brown wrote: > On Fri, Jun 10, 2011 at 10:27:25PM +0200, Rafael J. Wysocki wrote: > > > So, there are a few things to consider: > > > * Can the device do things like DMA? > > * Does the driver use a workqueue? > > * Does it use timers? > > > In all of the above cases your system suspend handling will require extra > > care to make sure those things won't get in the way of the suspend process. > > Yes, that's the quiesce operation I think myself or Alan mentioned. > > > It's probably fair to say that everithing depends on the subsystem, what it > > does and what it expects from the driver. In the extreme case, when the > > subsystem is like the platform bus type, the driver unfortunately is on its > > own and has to deal with the whole complexity. > > I'm pretty much only working with buses that have no infrastructure and > for which power is essentially orthogonal to the control bus itself - > that's a very large proportion of the embedded space. It really feels > like we could be doing a better job for drivers using these buses, > there's a lot of similarities in what many of them need but I can never > find the time to get my head round it confidently enough to actually > propose anything. I agree. That's one of the reasons why I introduced the struct dev_power_domain thing a while ago and the generic PM domains patchset I've just posted is a step in that direction. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
