Jean Delvare wrote: > Hi Hans, > >> This patch contains rudimentary suspend / resume support for the uguru, >> this protects the uguru and the driver against suspend / resume cycles, >> so there is no reason to unload the driver in your suspend / resume scripts. >> >> I'm not sure if this is needed, does the sysfs code itself guarantee >> that no sysfs attr read/write calls are in progress before starting a >> resume, if it does then this patch most likely isn't needed. > > Good question, I really don't know. If sysfs doesn't guarantee it, then > we should do something similar for all hardware monitoring drivers, > it's simple enough. > > Maybe you can raise the question on LKML, or maybe linux-pm-devel > (doesn't seem too active though) or otherwise ask anyone with more > power management knowledge than I do? > I'm not subscribed to LKML (too much mail from other lists already), maybe someone who is can forward this for me? My guess is that this protection is actually needed as in the end the sysfs reads / writes are just ordinary reads / writes and I don't think that the kernel guarantees all reads/writes to have completed when suspending, because that would be a real pain to guarantee for things like NFS, disks, etc. >> Except for >> protecting against this, it also checks the uguru is still in ready >> status after a resume, but that seems to be unnescesarry (as it seems >> that the uguru always is still ready after the resume). > > Well this patch shouldn't harm, even if it doesn't do anything > useful ;) so I guess I can take it. > I don't mind it getting applied either, that would keep upstream and my private copy nicely in sync. Regards, Hans
