On 9/3/06, Pavel Machek <pavel at ucw.cz> wrote: > > >That depends on the definition, but I think of suspend states as the ones > > >that require processes to be frozen before they can be entered. IMHO it is > > >quite clear that such states cannot be handled in the same way as those > > >that do not require the freezing of processes, so they are not the same. > > > > You are correct, processes do need to be frozen before a suspend. > > That's the prepare to suspend part of the suspend process, and > > the transtition is the suspending and finish is the un-freezing > > of the processes to resume execution. > > > > And those same steps are the same steps required to transition the > > system to a new operating point, whether it's suspend or change > > from 1.4GHz to 600MHz. > > No, processes are not frozen for simple cpu frequency change -- on > non-broken cpus. I didn't say cpu frequency changes freeze processes. I said a suspend does a prepare to suspend step (which freezes processes) and a cpu frequency change does a prepare to change frequency step (where it will run the driver notifier list to get drivers set to scale). They both do the same three steps: 1) prepare to transition 2) transition 3) finish transition That's one of my arguements as to why suspend states should be treated just like frequency states. David > Pavel > -- > (english) http://www.livejournal.com/~pavelmachek > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html >
