On Wed, Mar 19, 2008 at 02:22:00PM +0100, Rafael J. Wysocki wrote: > On Wednesday, 19 of March 2008, Greg KH wrote: > > On Mon, Mar 17, 2008 at 12:22:29AM +0100, Rafael J. Wysocki wrote: > > > From: Rafael J. Wysocki <rjw@xxxxxxx> > > > > > > Introduce 'struct pm_ops' representing a set of suspend and > > > hibernation operations for bus types, device classes and device > > > types. > > > > Ok, I must have missed the thread describing why we need to do this, so, > > why do we need to do this? What is this going to buy us in the end > > after everything is changed? > > There were many threads related to that. > > To summarize, the first purpose is to separate suspend (aka s2ram and standby) > callbacks from hibernation callbacks in such a way that the new callbacks won't > take arguments and the purpose of each of them will be clearly specified. This > has been requested multiple times by many people, including Linus himself, > and the reason is that within the current scheme if ->resume() is called, for > example, it's difficult to say why it's been called (ie. is it a resume from RAM or > from hibernation or a suspend/hibernation failure etc.?). > > The second purpose is to make the suspend/hibernation callbacks more flexible > so that device drivers can handle more than they can within the current scheme. > For example, some drivers may need to prevent new children of the device from > being registered before their ->suspend() callbacks are executed or they may > want to carry out some operations requiring the availability of some other > devices, not directly bound via the parent-child relationship, in order to prepare > for the execution of ->suspend(), etc. > > Ultimately, we'd like to stop using the freezing of tasks for suspend and > therefore the drivers' suspend/hibernation code will have to take care of > the handling of the user space during suspend/hibernation which would be > difficult within the current scheme, without the ->prepare() and ->complete() > callbacks. Ok, thanks. You might want to include this in the patch itself (hint, hint, hint...) greg k-h _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
