On Wed, 4 Aug 2004, David Brownell wrote: > > > Good question. I think that the PM core should have a routine that's > > > responsible for suspending all of a subtree. Instead it only has code > > > to do that for the degenerate subtree: the whole darn system! > > > > You're still missing my point. The PM core _can't_ have such a routine. > > Or if it does, the routine won't work for locking USB devices. > > > > Why not? In order to lock all the devices in a subtree the PM core first > > has to acquire the subsystem rwsem; otherwise the subtree could change out > > from under it. > > The subtree _needs_ to be able to change on the fly. And I'll > note that subsystem locks aren't a factor in the PM core today.
While it's true that the device tree needs to be able to change on the fly, it's just as true that it needs not to change at certain times. That's why the subsystem rwsems exist! As for the subsystem locks not being a factor in the PM core today... I said earlier that I foresaw this becoming a problem in the future. Alan Stern ------------------------------------------------------- This SF.Net email is sponsored by OSTG. Have you noticed the changes on Linux.com, ITManagersJournal and NewsForge in the past few weeks? Now, one more big change to announce. We are now OSTG- Open Source Technology Group. Come see the changes on the new OSTG site. www.ostg.com _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
