Hello, On Wed, Mar 06, 2024 at 08:05:15AM +0100, Linux regression tracking (Thorsten Leemhuis) wrote: > Hi, Thorsten here, the Linux kernel's regression tracker. > > Uwe, I noticed a report about a regression in bugzilla.kernel.org that > apparently is caused by a change of yours. As many (most?) kernel > developers don't keep an eye on it, I decided to forward it by mail. > > Note, you have to use bugzilla to reach the reporter, as I sadly[1] can > not CCed them in mails like this. > > Quoting from https://bugzilla.kernel.org/show_bug.cgi?id=218559 : > > > Commit 76fe464c8e64e71b2e4af11edeef0e5d85eeb6aa ("leds: pwm: Don't > > disable the PWM when the LED should be off") prevents stm32mp1xx based > > targets from entering suspend if pwm-leds exist, as the stm32 PWM driver > > refuses to enter suspend if any PWM channels are still active ("PWM 0 > > still in use by consumer" see stm32_pwm_suspend in drivers/pwm/stm32-pwm.c). > > > > Reverting the mentioned commit fixes this behaviour but I'm not > > certain if this is a problem with stm32-pwm or pwm-leds (what is the > > usual behaviour for suspend with active PWM channels?). I'd assume the following patch fixes this report. I didn't test it though. Best regards Uwe ---->8---- From: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> Subject: [PATCH] leds: pwm: Disable PWM when going to suspend On stm32mp1xx based machines (and others) a PWM consumer has to disable the PWM because an enabled PWM refuses to suspend. So check the LED_SUSPENDED flag and depending on that set the .enabled property. Link: https://bugzilla.kernel.org/show_bug.cgi?id=218559 Fixes: 76fe464c8e64 ("leds: pwm: Don't disable the PWM when the LED should be off") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> --- drivers/leds/leds-pwm.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c index 4e3936a39d0e..e1b414b40353 100644 --- a/drivers/leds/leds-pwm.c +++ b/drivers/leds/leds-pwm.c @@ -53,7 +53,13 @@ static int led_pwm_set(struct led_classdev *led_cdev, duty = led_dat->pwmstate.period - duty; led_dat->pwmstate.duty_cycle = duty; - led_dat->pwmstate.enabled = true; + /* + * Disabling a PWM doesn't guarantee that it emits the inactive level. + * So keep it on. Only for suspending the PWM should be disabled because + * otherwise it refuses to suspend. The possible downside is that the + * LED might stay (or even go) on. + */ + led_dat->pwmstate.enabled = !(led_cdev->flags & LED_SUSPENDED); return pwm_apply_might_sleep(led_dat->pwm, &led_dat->pwmstate); } base-commit: 15facbd7bd3dbfa04721cb71e69954eb4686cb9e ---->8---- -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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