Hi! > > This would be doing something like partial-tree suspends, but I'm not sure > > if this is best done in the kernel or in userspace with a proper tool. > > Hrm... I think it's more complex than that. We need 2 way communication > between parents & childs. For example, if a parent is informed when a > child entered an idle-suspend state (local dynamic PM), it can enter > itself into some kind of suspend state when all it's offspring is in > such a state (like USB bus suspend when devices are idle, Apple does > that afaik, or did that in MacOS 9). > > But that means child -> parent notifications > > Also, states tend to be bus specific (PCI D states, USB states, ...) Perhaps we should have more types like pci_power_t, then, and pass those around? Whether notification needs to be sent up or down seems bus-specific, too, so maybe it makes sense to do this per-bus? > > > For user suspends (made through sysfs) the user may want to convey > > > arbitrary information to a driver, things like which clocks to turn > > > off, which power level to change to, and so on. This information > > > will vary from driver to driver, and the PM core shouldn't even try to > > > impose any sort of structure on it. I think the best approach will be > > > to pass to the driver a character pointer giving the data written to > > > /sys/.../power/state, so that users can send whatever they want just > > > by writing it to the file. This means adding an additional field to > > > pm_message_t. > > > > Uh, that would really suck. This would entail a string parser in every > > driver, which is what we wanted to get away from with sysfs. A better way > > would be to have a driver export a file with the specific features that it > > supports encoded in a meaningful and efficient way (i.e. a fixed-length > > string, character, or constant). > > > > What aboout a new IRC meeting to discuss those things ? Why not... But having it in European-friendly time would certainly help. Pavel -- People were complaining that M$ turns users into beta-testers... ...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!
