On Fri, 26 Jan 2007, Oliver Neukum wrote: > Am Donnerstag, 25. Januar 2007 20:55 schrieb Alan Stern: > > Now something we _could_ use is an API allowing userspace to do runtime > > suspend/resume of USB devices. The /sys/devices/.../power/state thing is > > deprecated and will be removed soon. I posted a patch for this purpose > > some time ago: > > > > http://marc.theaimsgroup.com/?l=linux-usb-devel&m=115151191222054&w=2 > > > > Greg said that it wasn't needed yet. But eventually something like it > > _will_ be needed. > > Upon further thought, why yet another USB specific mechanism?
How quickly they forget... :-) Remember all those endless discussions on the linux-pm list about runtime PM and the PM sysfs API? In the end people agreed that /sys/devices/.../power/state was no good. People also agreed that runtime power management is inherently device-specific (or at the very least, bus-specific) and should not be constrained to fit in a single inflexible mold. For example, USB devices have two power states: on and suspended. PCI devices can have four states: D0 - D3hot. Other devices have other sets of states and other parameters to control them (which power lines and which clocks should be gated on, etc.). In short, our suspend/resume API _has_ to be USB-specific. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
