On Sunday, September 23, 2012, Lan Tianyu wrote: > 于 2012/9/22 20:08, Rafael J. Wysocki 写道: > > So, my current idea is why don't we handle that through PM QoS? I mean we have > > a means to specify per-device PM QoS wakeup latency constraits and expose it to > > user space on a per-device basis. I suppose we can we can handle the > > "don't remove power from this device" requirement in a similar way, i.e. add > > something like per-device PM QoS flags specifying binary requirements regarding the > > low-power states the device can be put into by ACPI or another platform-dependent > > mechanism, like "the state to go into cannot be zero power", "remote wakeup is > > required" etc. > So according your suggestion, we should add a new pm Qos which may name "remote > wakeup > is required" or "power off is allowed"(this may be better since there are other > reasons > for not enable to power off device except for remote wakeup enable). Actually, I think we need both. > When we try to power off devices, we should take it into account, right? Yes, that's the idea. If I have the time next week, which depends on some things beyond my control unfortunately, I'll try to prepare some proof-of-concept implementation of this. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
