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| author |   Hans de Goede <hdegoede@redhat.com> | 2020-11-09 11:57:26 +0100 |
|---|---|---|
| committer |   Thierry Reding <thierry.reding@gmail.com> | 2020-12-17 14:18:49 +0100 |
| commit | e3aa45f2f88b6779ab798c63a4deb7ddff949ac7 (patch) | |
| tree | 78fa402da641839eb1d8d2d0b6ec64d8fb41baa1 /drivers/pwm | |
| parent | pwm: lpss: Use DPM_FLAG_NO_DIRECT_COMPLETE instead of declaring a prepare handler (diff) | |
| download | linux-dev-e3aa45f2f88b6779ab798c63a4deb7ddff949ac7.tar.xz linux-dev-e3aa45f2f88b6779ab798c63a4deb7ddff949ac7.zip | |
pwm: lpss: Set DPM_FLAG_SMART_SUSPEND on Cherry Trail devices
As the comment above the code setting the DPM_FLAG_NO_DIRECT_COMPLETE
flag explains:
/*
* On Cherry Trail devices the GFX0._PS0 AML checks if the controller
* is on and if it is not on it turns it on and restores what it
* believes is the correct state to the PWM controller.
* Because of this we must disallow direct-complete, which keeps the
* controller (runtime)suspended, on resume to avoid 2 issues:
* 1. The controller getting turned on without the linux-pm code
* knowing about this. On devices where the controller is unused
* this causes it to stay on during the next suspend causing high
* battery drain (because S0i3 is not reached)
* 2. The state restoring code unexpectedly messing with the controller
*/
The pm-core must not skip resume to avoid the GFX0._PS0 AML code messing
with the PWM controller behind our back. But leaving the controller
runtime-suspended (skipping runtime-resume + normal-suspend) during
suspend is fine. Set the DPM_FLAG_SMART_SUSPEND flag to allow this.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-lpss-platform.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-lpss-platform.c b/drivers/pwm/pwm-lpss-platform.c index ac33861edb48..986786be1e49 100644 --- a/drivers/pwm/pwm-lpss-platform.c +++ b/drivers/pwm/pwm-lpss-platform.c @@ -69,9 +69,13 @@ static int pwm_lpss_probe_platform(struct platform_device *pdev) * this causes it to stay on during the next suspend causing high * battery drain (because S0i3 is not reached) * 2. The state restoring code unexpectedly messing with the controller + * + * Leaving the controller runtime-suspended (skipping runtime-resume + + * normal-suspend) during suspend is fine. */ if (info->other_devices_aml_touches_pwm_regs) - dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE); + dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE| + DPM_FLAG_SMART_SUSPEND); pm_runtime_set_active(&pdev->dev); pm_runtime_enable(&pdev->dev); |