Commit ad07277e authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI / PM: Hold acpi_scan_lock over system PM transitions 



Bad things happen if ACPI hotplug events are handled during system
PM transitions, especially if devices are removed as a result.
To prevent those bad things from happening, acquire acpi_scan_lock
when a PM transition is started and release it when that transition
is complete or has been aborted.

This fixes resume lockup on my test-bed Acer Aspire S5 that happens
when Thunderbolt devices are disconnected from the machine while
suspended.

Also fixes the analogous problem for Mika Westerberg on an
Intel DZ77RE-75K board.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: default avatarToshi Kani <toshi.kani@hp.com>
parent 1aaac071

drivers/acpi/sleep.c

+24 −15
Original line number Diff line number Diff line
@@ -420,10 +420,21 @@ static void acpi_pm_finish(void) 
}



/**

 *	acpi_pm_end - Finish up suspend sequence.

 * acpi_pm_start - Start system PM transition.

 */

static void acpi_pm_start(u32 acpi_state)

{

	acpi_target_sleep_state = acpi_state;

	acpi_sleep_tts_switch(acpi_target_sleep_state);

	acpi_scan_lock_acquire();

}



/**

 * acpi_pm_end - Finish up system PM transition.

 */

static void acpi_pm_end(void)

{

	acpi_scan_lock_release();

	/*

	 * This is necessary in case acpi_pm_finish() is not called during a

	 * failing transition to a sleep state.
@@ -451,21 +462,19 @@ static u32 acpi_suspend_states[] = { 
static int acpi_suspend_begin(suspend_state_t pm_state)

{

	u32 acpi_state = acpi_suspend_states[pm_state];

	int error = 0;

	int error;



	error = (nvs_nosave || nvs_nosave_s3) ? 0 : suspend_nvs_alloc();

	if (error)

		return error;



	if (sleep_states[acpi_state]) {

		acpi_target_sleep_state = acpi_state;

		acpi_sleep_tts_switch(acpi_target_sleep_state);

	} else {

		printk(KERN_ERR "ACPI does not support this state: %d\n",

			pm_state);

		error = -ENOSYS;

	if (!sleep_states[acpi_state]) {

		pr_err("ACPI does not support sleep state S%u\n", acpi_state);

		return -ENOSYS;

	}

	return error;



	acpi_pm_start(acpi_state);

	return 0;

}



/**
@@ -631,10 +640,8 @@ static int acpi_hibernation_begin(void) 
	int error;



	error = nvs_nosave ? 0 : suspend_nvs_alloc();

	if (!error) {

		acpi_target_sleep_state = ACPI_STATE_S4;

		acpi_sleep_tts_switch(acpi_target_sleep_state);

	}

	if (!error)

		acpi_pm_start(ACPI_STATE_S4);



	return error;

}
@@ -713,8 +720,10 @@ static int acpi_hibernation_begin_old(void) 
	if (!error) {

		if (!nvs_nosave)

			error = suspend_nvs_alloc();

		if (!error)

		if (!error) {

			acpi_target_sleep_state = ACPI_STATE_S4;

			acpi_scan_lock_acquire();

		}

	}

	return error;

}

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