Suspend/resume call path for ACPI_STATE_S1:
2006/11/17
Jun Sun

Note:
* Kernel is 2.6.15 patched for original FC5.  Run-time system is vmplayer.  Customized configuration.

* The callgraph is based on echo "standby" to /sysfs/power/state

* An alternative way to start suspend path is through /proc/???/acpi
	in drivers/acpi/sleep/proc.c through calling pm_suspend() in 
	kernel/power/main.c

TODO:

* Did not track what devices are on some of the lists.  Help?

[USER] echo -n "standby" > /sysfs/power/state

  + state_store() 
      -	enter_state(ACPI_STATE_S1) 
	  - suspend_prepare() 
	      -	pm_prepare_console()
		  - set_console(SUSPEND_CONSOLE);
		    vt_waitactive(SUSPEND_CONSOLE);
		    orig_kmsg = kmsg_redirect;
		    kmsg_redirect = SUSPEND_CONSOLE;
	       	freeze_processes() 
		  - for (each thread p) freeze(p) 
			p->flags |= PF_FREEZE
		if (pm_ops->prepare) pm_ops->prepare() 
		  =>acpi_pm_prepare() 
		      -	acpi_sleep_prepare() 
			  - if (acpi_state == ACPI_STATE_S3) {
				acpi_set_firmware_waking_vector(acpi_wakeup_address);
			    }
			    ACPI_FLUSH_CPU_CACHE();
			    acpi_enable_wakeup_device_prep(acpi_state); 
			      -	for each dev in acpi_wakeup_device_list {
				    acpi_enable_wakeup_device_power(dev); 
				      -	For each resource handle of dev
					    acpi_power_on(dev->wakeup.resources.handles[i]);
				}
			    acpi_gpe_sleep_prepare(acpi_state); /* Disable all wakeup GPEs before poweroff */
			    acpi_enter_sleep_state_prep(acpi_state); /* eval acpi objects */
		device_suspend() 
		  - for each dev in dpm_active {
			suspend_device(dev, state);
			  - dev->bus->suspend(dev, state);
		    }
	    suspend_enter() 
	      - device_power_down(PMSG_SUSPEND) /* shutdown special devices */
		  - foreach (dev on dpm_off_irq) {
			suspend_device(dev, state);
			  - dev->bus->suspend(dev, state);
		    }
		    sysdev_suspend(state);
		      - /* Suspend all system devices */
			/* pseudo-bus for system 'devices' (cpus, PICs, timers, etc) */
		pm_ops->enter(state);
		  =>acpi_pm_enter()
		      - if (pm_state > PM_SUSPEND_STANDBY) {
			    acpi_save_state_mem();
			}
			acpi_enable_wakeup_device(acpi_state);
			switch (pm_state) {
			    case PM_SUSPEND_STANDBY: acpi_enter_sleep_state(ACPI_STATE_S1);
			    case PM_SUSPEND_MEM : do_suspend_lowlevel();
			    case PM_SUSPEND_DISK : acpi_enter_sleep_state(ACPI_STATE_S4);
			    case PM_SUSPEND_MAX: acpi_power_off();
			}
		device_power_up();
		  - sysdev_resume();  /* Bring system devices back to life */
		    dpm_power_up();  /* power on devices on dpm_off_irq list */
		      - foeach (dev on dpm_off_irq list) {
			    resume_device(dev);
			}
	    suspend_finish()
	      - device_resume();
		  - dpm_resume();
		      - foeach (dev on dpm_off list) {
			    resume_device(dev);
			}
		thaw_processes();
		  - foreach (thread p) {
			thaw_process(p);
			  - p->flags &= ~PF_FROZEN;
			    wake_up_process(p);
		    }
		    schedule();
		enable_nonboot_cpus();
		if (pm_ops->finish) pm_ops->finish(state);
		  =>acpi_pm_finish()
		      - acpi_leave_sleep_state(acpi_state);
			acpi_disable_wakeup_device(acpi_state);
			acpi_set_firmware_waking_vector((acpi_physical_address) 0);
		pm_restore_console();
		  - set_console(orig_fgconsole);
		    kmsg_redirect = orig_kmsg;