[...] >> Are there any major reasons why the appended patch (obviously untested) won't >> work, then? > > OK, there is a reason, which is the optimizations bundled into > pm_runtime_force_*, because (a) the device may be left in runtime suspend > by them (in which case amba_pm_suspend_early() in my patch should not run) > and (b) pm_runtime_force_resume() may decide to leave it suspended (in which > case amba_pm_suspend_late() in my patch should not run). Exactly. > > [BTW, the "leave the device suspended" optimization in pm_runtime_force_* > is potentially problematic too, because it requires the children to do > the right thing, which effectively means that their drivers need to use > pm_runtime_force_* too, but what if they don't want to reuse their > runtime PM callbacks for system-wide PM?] Deployment of pm_runtime_force_suspend() should generally be done for children devices first. If some reason that isn't the case, it's expected that the call to pm_runtime_set_suspended() invoked from pm_runtime_force_suspend(), for the parent, should fail and thus abort system suspend. > > Honestly, I don't like the way this is designed. IMO, it would be better > to do the optimizations and all in the bus type middle-layer code instead > of expecting drivers to use pm_runtime_force_* as their system-wide PM > callbacks (and that expectation should at least be documented, which I'm > not sure is the case now). But whatever. > > It all should work the way it does now without pm_runtime_force_* if (a) the > bus type's PM callbacks are changed like in the last patch and the drivers > (b) point their system suspend callbacks to the runtime PM callback routines > and (c) set DPM_FLAG_SMART_SUSPEND and DPM_FLAG_LEAVE_SUSPENDED for the > devices (if they need to do the PM in ->suspend and ->resume, they may set > DPM_FLAG_AVOID_RPM too). > > And if you see a reason why that won't work, please let me know. I will have look and try out the series by using my local "runtime PM test driver". I get back to you with an update on this. Kind regards Uffe
