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: > > > Am Mittwoch 10 Oktober 2007 schrieb Alan Stern: > It's possible to defer the unbinding until the post-SUSPEND or > post-HIBERNATE notifier call, since that occurs after all the resume > methods have run and before userspace is unfrozen. We're okay as far Then I think this is the time to do it. > as URBs and endpoints are concerned; the code in usb_suspend_both() > flushes all the endpoints and prevents further submissions. > > > > 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. > complete transparency anyway. For instance, if userspace has opened a > device file for a non-compliant driver then the file descriptor will > become unusable when the driver is unbound, regardless of exactly when > the unbind occurs. Yes, unavoidably so. > Of course there's always the other approach -- solve the problem by > adding suspend and resume methods to every driver! Are you volunteering? > Remember also that an eventual goal is to eliminate the freezer. > What's the right approach when userspace never does get frozen? I am not sure about the wisdom of this approach. > Simply adding suspend/resume support is looking more and more > attractive... 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. 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