Re: Drivers without suspend/resume/reset-resume support
Oliver Neukum <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
Am Donnerstag 11 Oktober 2007 schrieb Alan Stern: > On Thu, 11 Oct 2007, Oliver Neukum wrote: > > > > > > One way around the problem would be to unbind these bad drivers before > > > > > the suspend begins, say in a notifier routine. That would leave a > > > > > > > > Problematic. You'd have to get the order of doing stuff exactly right. > > > > > > What order are you concerned about? It will be impossible to have > > > > Blocking new device additions vs. calling disconnect. > > If we disconnect the bad drivers after khubd has gone to sleep then no > new devices will be added. There's still the possibility of userspace > causing a bind via sysfs, though. Driver loading, change of configuration, ... Did you check the other code paths? > > > Of course there's always the other approach -- solve the problem by > > > adding suspend and resume methods to every driver! > > > > Are you volunteering? > > How many drivers are we talking about? Dozens, which will require testing. > > Resumption may involve IO, which therefore may fail. I cannot see the reason > > to not count the lack of a resume method as a failure. We'll have to deal with > > them anyway, especially for reset_resume. > > If a driver doesn't have a suspend or resume method, then resuming it > can't involve I/O. :-) You still can have IO to a hub to wake the device. > You appear to be saying that if a driver doesn't have a resume method, > or the resume method returns an error, then the driver should be > unbound as soon as possible. For non-system non-auto resumes this is Yes. > right away, but for system resumes it isn't until the driver core is > stable again. Likewise, non-system suspends should fail if a driver Yes. > doesn't have a suspend method (I'm not so sure about this part). Yes. Regards Oliver ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel