pwm: lpss: Check PWM powerstate after resume on Cherry Trail devices (6a425ecd) · Commits · 戴 / test

The _PS0 method for the integrated graphics on some Cherry Trail devices (observed on a HP Pavilion X2 10-p0XX) turns on the PWM chip (puts it in D0), causing an inconsistency between the state the pm-core thinks it is in (left runtime suspended as it was before the suspend/resume) and the state it actually is in. Interestingly enough this is done on a device where the pwm controller is not used for the backlight at all, since it uses an eDP panel. On devices where the PWM is used this is not a problem since we will resume it ourselves anyways. This inconsistency causes us to never suspend the pwm controller again, which causes the device to not be able to reach S0ix states when suspended. This commit adds a resume-complete handler, which when we think the device is still run-time suspended checks the actual power-state and if necessary updates the rpm-core's internal state. This fixes the Pavilion X2 10-p0XX not reaching S0ix states when suspended. Reviewed-by:

Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by:

Hans de Goede <hdegoede@redhat.com> Signed-off-by:

Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-lpss-platform.c

+22 −3

Original line number	Diff line number	Diff line
		@@ -30,6 +30,7 @@ static const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
		.clk_rate = 19200000,
		.npwm = 1,
		.base_unit_bits = 16,
		.check_power_on_resume = true,
		};

		/* Broxton */
		@@ -74,9 +75,27 @@ static int pwm_lpss_remove_platform(struct platform_device *pdev)
		return pwm_lpss_remove(lpwm);
		}

		static SIMPLE_DEV_PM_OPS(pwm_lpss_platform_pm_ops,
		pwm_lpss_suspend,
		pwm_lpss_resume);
		static void pwm_lpss_complete(struct device *dev)
		{
		struct pwm_lpss_chip *lpwm = dev_get_drvdata(dev);
		int ret, state;

		/* The PWM may be turned on by AML code, update our state to match */
		if (pm_runtime_suspended(dev) && lpwm->info->check_power_on_resume) {
		pm_runtime_disable(dev);

		ret = acpi_device_get_power(ACPI_COMPANION(dev), &state);
		if (ret == 0 && state == ACPI_STATE_D0)
		pm_runtime_set_active(dev);

		pm_runtime_enable(dev);
		}
		}

		static const struct dev_pm_ops pwm_lpss_platform_pm_ops = {
		.complete = pwm_lpss_complete,
		SET_SYSTEM_SLEEP_PM_OPS(pwm_lpss_suspend, pwm_lpss_resume)
		};

		static const struct acpi_device_id pwm_lpss_acpi_match[] = {
		{ "80860F09", (unsigned long)&pwm_lpss_byt_info },

drivers/pwm/pwm-lpss.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -30,6 +30,8 @@ struct pwm_lpss_boardinfo {
		unsigned int npwm;
		unsigned long base_unit_bits;
		bool bypass;
		/* Some devices have AML code messing with the state underneath us */
		bool check_power_on_resume;
		};

		struct pwm_lpss_chip pwm_lpss_probe(struct device dev, struct resource *r,

Admin message