On Sun, 6 Dec 2009, Rafael J. Wysocki wrote: > > > It all looks terminally broken: you force async suspend for all PCI > > drivers, even when it makes no sense. > > I'm not exactly sure what you're referring to. The async suspend is not > forced, it just tells the PM core that it can execute PCI suspend/resume > callbacks in parallel as long as the devices in question don't depend on each > other. That's exactly what I mean by forcing async suspend/resume. You don't know the ordering rules for PCi devices. Multi-function PCI devices commonly share registers - they're on the same chip, after all. And even when the _hardware_ is totally independent, we often have discovery rules and want to initialize in order because different drivers will do things like unregister entirely on suspend, and then re-register on resume. Imagine the mess when two ethernet devices randomly end up coming up with different names (eth0/eth1) depending on subtle timing issues. THAT is why we do things in order. Asynchronous programming is _hard_. Just deciding that "all PCI devices can always be resumed and suspended asynchronously" is a much MUCH bigger decision than you seem to have even realized. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
