On Tue, 3 Jul 2007, Matthew Garrett wrote: > On Tue, Jul 03, 2007 at 05:16:37PM -0400, Alan Stern wrote: > > On Tue, 3 Jul 2007, Matthew Garrett wrote: > > > But that's fine - "Are we undergoing a systemwide suspend" is an easy > > > question to ask. Freezing processes instead means that most of those > > > paths will never be tested. > > > > The question is easy to ask, but it's not so easy to figure out what > > you should do if the answer is Yes. Freezing processes instead means > > that those "untested" paths -- in many, many drivers -- won't have to > > exist at all. > > We're used to the idea of applications blocking when a resource they're > using goes away - NFS has done it forever. You persist in evading my point. I'm not worried about applications; I'm worried about drivers. Let me put it explicitly: You're writing a driver. You're working on the read, write, or probe method. You add code to check if a system sleep is underway. Suppose the answer is Yes -- what does your driver do next? Make your answer as detailed as you reasonably can. And be careful to arrange things so that an ongoing I/O operation doesn't get messed up when your suspend method is called. Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
