On Sat, 4 Dec 2004, Pavel Machek wrote: > Well, imagine battery-backed usb display. You might want to write "I'm > suspended to RAM" on the display when machine goes suspend-to-RAM. That could always be done by a userspace program as part of the overall system sleep procedure. In fact, this would be more appropriate than having a device driver do it... > Hmm, if user than disconnects the display from the machine and resumes > machine, it will say "I'm suspended to RAM" even through machine is > running happily... I think we don't need to be held accountable for what hardware does when it's not connected to the computer! :-) > If the driver wants to implement suspend as disconnect... well, why > not. But for example usb disk, you probably want it to be left mounted > during suspend but unplug should probably trigger emergency unmount. Yes, certainly. David's original point was that if VBUS power isn't available during system sleep, then sleep is indistinguishable from disconnect as far as USB is concerned. So a sleep transition would already be enough to trigger an emergency unmount. In practice, of course, the hotplug scripts should be set up so that they unmount such drives cleanly at the start of the sleep transition. Alan Stern
