Hi! > > I don't like this notion of "stop" separated from power states anyway, I > > think it just doesn't work in practice. > > Yeah, after giving it some additional thought, I think there are better ways. > > > > > Ben. > > > > Ok, here's a new idea. > > For many devices "->suspend" and "->resume" with pm_message_t is exactly what > we need. However, as we support more advanced power management features, such > as runtime power management, or power containers, we need something a little > more specific. The exact power state must be specified among other > issues. Okay, maybe. But not by adding 3 new callbacks that mirror existing functionality. > We might do something like this: > > Keep "->suspend" and "->resume" around unchanged. (so the states would > probably remain as PMSG_FREEZE and PMSG_SUSPEND). If the driver doesn't > support the more advanced PM methods just use these. They work well enough > for system sleep states etc. > > Alternatively drivers could support a more rich power management interface > via the following methods: > > > change_state - changes a device's power state > > change_state(struct device * dev, pm_state_t state, struct system_state * sys_state, int reason); > @dev - the device > @state - the target device-specific power state > @sys_state - a data structure containing information about the intended global system power state > @reason - why the state must be changed (ex. RUNTIME_PM, > SYSTEM_SLEEP, SYSTEM_RESUME, etc.) If drivers really need to know system state and reason, just put it into pm_message_t. I wanted to add "flags" there from the begining, serving similar purpose as your "reason". > halt - acts somewhat like PMSG_FREEZE, stops device activity, doesn't change power state > > halt(struct device * dev, struct system_state * sys_state, int reason); > @dev - the device > @sys_state - a data structure containing information about the intended global system power state > @reason - why we are halting operation (ex. RUNTIME_CHANGES (like cpufreq), SYSTEM_SLEEP, SHUTDOWN, REBOOT) If it is similar to PMSG_FREEZE, just pass PMSG_FREEZE and put * sys_state and reason into pm_message_t. > contine - resumes from a "halt" > > continue(struct device * dev, struct system_state * sys_state, int reason); > @dev - the device > @sys_state - a data structure containing information about the intended global system power state > @reason - why we are resuming operation (ex. RUNTIME_CHANGES (like cpufreq), SYSTEM_RESUME) Now, here you have a point. resume() should get pm_message_t, too. This should be rather easy to change (simple matter of coding), and we have agreed before that it is good idea. Patches welcome. Pavel -- Boycott Kodak -- for their patent abuse against Java.
