On Tue 2009-04-07 17:31:13, Alan Stern wrote: > On Tue, 7 Apr 2009, Rafael J. Wysocki wrote: > > > > >> I works on an hardware that have the gsm connect to wm8753 and the > > > >> bluetooth subsystem > > > >> too direct connected. So I would like that a phone call for example > > > >> remains on during > > > >> system suspend. With this approch I can disable suspend of an entire > > > >> subtree of device, > > > >> that can be used by other hardware component. This change avoid any > > > >> specific change to the > > > >> driver. > > > >> > > > > > > > > Why do you want to avoid changing the driver, actually? > > > > > > > > Rafael > > > > > > > > > > > Because, the driver may be connected to other device and you must change > > > the entire > > > set. This simple modification can help to share devices on an embedded > > > board and control > > > suspend/resume enable from user space. I don't know if it can be usefull > > > on broken board/device too. Do you see any possible risk with this > > > change? > > > > Yes, a (rather high) risk of abuse. > > > > > When I write it I try to have a simple modification on linux-pm part. > > > > So, basically, you'd like to introduce an interface allowing the user space to > > tell the kernel which devices not to suspend, because there may be some > > dependencies between devices that the kernel presumably doesn't know of. > > > > Well, what about teaching these dependencies to the kernel, so that it > > can take them into account by itself? > > Isn't that exactly what the patch already does? It lets the kernel > know that when the "don't-suspend" flag is set for a device then the > entire sub-tree rooted at that device should remain unsuspended. Well.... userspace should not have to decide this. If userspace tells kernel not to suspend video card (on PC/ACPI), then we either honour the request, or violate ACPI spec (and probably break suspend). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
