On Mon, 7 Dec 2009, Linus Torvalds wrote: > On Mon, 7 Dec 2009, Alan Stern wrote: > > > > It only seems that way because you didn't take into account devices > > that suspend synchronously but whose children suspend asynchronously. > > But why would I care? If somebody suspends synchronously, then that's what > he wants. It doesn't mean he wants to block unrelated devices from suspending asynchronously, merely because they happen to come earlier in the list. > > A synchronous suspend routine for a device with async child suspends > > would have to look just like your usb_node_suspend(): > > Sure. But that sounds like a "Doctor, it hurts when I do this" situation. > Don't do that. > > Make the USB host controller do its suspend asynchronously. We don't > suspend PCI bridges anyway, iirc (but I didn't actually check). And at > worst, we can make the PCI _bridges_ know about async suspends, and solve > it that way - without actually making any normal PCI drivers do it. This sounds suspiciously like pushing the problem up a level and hoping it will go away. (Sometimes that even works.) In the end it isn't a very big issue. Using one vs. two passes in dpm_suspend() is pretty unimportant. Alan Stern P.S.: In fact I planned all along to handle USB host controllers asynchronously anyway, since their resume routines contain some long delays. I was merely using them as an example. _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
