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Commit d5919dcc authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

Revert "PM / QoS: Fix device resume latency PM QoS" 



This reverts commit 0cc2b4e5 (PM / QoS: Fix device resume latency PM
QoS) as it introduced regressions on multiple systems and the fix-up
in commit 2a9a86d5 (PM / QoS: Fix default runtime_pm device resume
latency) does not address all of them.

The original problem that commit 0cc2b4e5 was attempting to fix
will be addressed later.

Fixes: 0cc2b4e5 (PM / QoS: Fix device resume latency PM QoS)
Reported-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5ba25724

Documentation/ABI/testing/sysfs-devices-power

+1 −3
Original line number Diff line number Diff line
@@ -211,9 +211,7 @@ Description: 
		device, after it has been suspended at run time, from a resume

		request to the moment the device will be ready to process I/O,

		in microseconds.  If it is equal to 0, however, this means that

		the PM QoS resume latency may be arbitrary and the special value

		"n/a" means that user space cannot accept any resume latency at

		all for the given device.

		the PM QoS resume latency may be arbitrary.



		Not all drivers support this attribute.  If it isn't supported,

		it is not present.

drivers/base/cpu.c

+1 −2
Original line number Diff line number Diff line
@@ -377,8 +377,7 @@ int register_cpu(struct cpu *cpu, int num) 


	per_cpu(cpu_sys_devices, num) = &cpu->dev;

	register_cpu_under_node(num, cpu_to_node(num));

	dev_pm_qos_expose_latency_limit(&cpu->dev,

					PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);

	dev_pm_qos_expose_latency_limit(&cpu->dev, 0);



	return 0;

}

drivers/base/power/domain_governor.c

+23 −30
Original line number Diff line number Diff line
@@ -14,20 +14,23 @@ 
static int dev_update_qos_constraint(struct device *dev, void *data)

{

	s64 *constraint_ns_p = data;

	s64 constraint_ns = -1;

	s32 constraint_ns = -1;



	if (dev->power.subsys_data && dev->power.subsys_data->domain_data)

		constraint_ns = dev_gpd_data(dev)->td.effective_constraint_ns;



	if (constraint_ns < 0)

	if (constraint_ns < 0) {

		constraint_ns = dev_pm_qos_read_value(dev);



	if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)

		return 0;



		constraint_ns *= NSEC_PER_USEC;

	}

	if (constraint_ns == 0)

		return 0;



	if (constraint_ns < *constraint_ns_p || *constraint_ns_p < 0)

	/*

	 * constraint_ns cannot be negative here, because the device has been

	 * suspended.

	 */

	if (constraint_ns < *constraint_ns_p || *constraint_ns_p == 0)

		*constraint_ns_p = constraint_ns;



	return 0;
@@ -60,14 +63,10 @@ static bool default_suspend_ok(struct device *dev) 


	spin_unlock_irqrestore(&dev->power.lock, flags);



	if (constraint_ns == 0)

	if (constraint_ns < 0)

		return false;



	if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)

		constraint_ns = -1;

	else

	constraint_ns *= NSEC_PER_USEC;



	/*

	 * We can walk the children without any additional locking, because

	 * they all have been suspended at this point and their
@@ -77,19 +76,14 @@ static bool default_suspend_ok(struct device *dev) 
		device_for_each_child(dev, &constraint_ns,

				      dev_update_qos_constraint);



	if (constraint_ns < 0) {

		/* The children have no constraints. */

		td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;

		td->cached_suspend_ok = true;

	} else {

		constraint_ns -= td->suspend_latency_ns + td->resume_latency_ns;

	if (constraint_ns > 0) {

			td->effective_constraint_ns = constraint_ns;

			td->cached_suspend_ok = true;

		} else {

			td->effective_constraint_ns = 0;

		}

		constraint_ns -= td->suspend_latency_ns +

				td->resume_latency_ns;

		if (constraint_ns == 0)

			return false;

	}

	td->effective_constraint_ns = constraint_ns;

	td->cached_suspend_ok = constraint_ns >= 0;



	/*

	 * The children have been suspended already, so we don't need to take
@@ -151,13 +145,12 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd, 
		td = &to_gpd_data(pdd)->td;

		constraint_ns = td->effective_constraint_ns;

		/* default_suspend_ok() need not be called before us. */

		if (constraint_ns < 0)

		if (constraint_ns < 0) {

			constraint_ns = dev_pm_qos_read_value(pdd->dev);



		if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)

			continue;



			constraint_ns *= NSEC_PER_USEC;

		}

		if (constraint_ns == 0)

			continue;



		/*

		 * constraint_ns cannot be negative here, because the device has

drivers/base/power/qos.c

+1 −1
Original line number Diff line number Diff line
@@ -189,7 +189,7 @@ static int dev_pm_qos_constraints_allocate(struct device *dev) 
	plist_head_init(&c->list);

	c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;

	c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;

	c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;

	c->no_constraint_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;

	c->type = PM_QOS_MIN;

	c->notifiers = n;

drivers/base/power/runtime.c

+1 −1
Original line number Diff line number Diff line
@@ -253,7 +253,7 @@ static int rpm_check_suspend_allowed(struct device *dev) 
	    || (dev->power.request_pending

			&& dev->power.request == RPM_REQ_RESUME))

		retval = -EAGAIN;

	else if (__dev_pm_qos_read_value(dev) == 0)

	else if (__dev_pm_qos_read_value(dev) < 0)

		retval = -EPERM;

	else if (dev->power.runtime_status == RPM_SUSPENDED)

		retval = 1;