On Wed, 26 Aug 2009, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rjw@xxxxxxx> > > Theoretically, the total time of system sleep transitions (suspend > to RAM, hibernation) can be reduced by running suspend and resume > callbacks of device drivers in parallel with each other. However, > there are dependencies between devices such that, for example, we may > not be allowed to put one device into a low power state before > anohter one has been suspended (e.g. we cannot suspend a bridge > before suspending all devices behind it). In particular, we're not > allowed to suspend the parent of a device before suspending the > device itself. Analogously, we're not allowed to resume a device > before resuming its parent. > In this version of the patch the async threads started to execute > the resume callbacks of specific device don't exit immediately having > done that, but search dpm_list for devices whose PM dependencies have > already been satisfied and execute their callbacks without waiting. Given this design, why bother to invoke device_resume() for the async devices? Why not just start up a bunch of async threads, each of which calls async_resume() repeatedly until everything is finished? (And rearrange async_resume() to scan the list first and do the actual resume second.) The same goes for the noirq versions. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
