Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes: > On Fri, 20 Jul 2007 david@xxxxxxx wrote: >> > Userspace can submit I/O requests. Someone will have to audit every >> > driver to make sure that such I/O requests don't cause a quiesced >> > device to become active. If the device is active, it will make the >> > memory snapshot inconsistent with the on-device data. >> >> assuming this is the suspend-from-ram after a kexec back from the >> write-to-disk kernel I don't think you are correct. >> >> when doing a suspend-to-ram you get to a point where you just don't use >> any userspace. > What do you mean? How can you prevent user tasks from running? That's > basically what the freezer does, and the whole point of this approach > is to eliminate the freezer. Right? Presumably no tasks at all would be scheduled. >> from that point on you are just walking the device tree >> putting things into low-power mode. This is the point where we are talking >> about jumping to. > Yes. And putting things into low-power mode requires the ability to > run the scheduler, which means that user tasks can be scheduled, which > means that they can run. Does it really (fundamentally) require scheduling tasks, particularly in the case that the devices have already been put in the "quiesced" state? -- Jeremy Maitin-Shepard _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
