Re: [PATCH] led: core: Fix race on software blink cancellation

[Pavel Machek]

Hi!

> Any comments? I'd like to have some acks before applying
> this patch.

I can't say I like it.

> > Commit d23a22a74fde ("leds: delay led_set_brightness if stopping soft-blink")
> > made a modifications to the LED core allowing for led_set_brightness() to be
> > called from hard-irq context when soft blink is being handled in soft-irq.
> > 
> > Since that time LED core has undergone modifications related to addition of
> > generic support for delegating brightness setting to a workqueue as well as
> > subsequent fixes for blink setting use cases.
> > 
> > After that the LED core code became hard to maintain and analyze, especially
> > due to the imposed hard-irq context compatibility. It also turned out that
> > in some cases a LED remained off after executing following sequence of commands:
> > 
> > 1. echo timer > trigger
> > 2. echo 0 > brightness
> > 3. echo 100 > brightness
> > 
> > The reason was LED_BLINK_DISABLE operation delegated to a set_brightness_work,
> > triggered in 2., which was handled after 3. took effect.

Could we wait for delayed work to be done before setting the
brightness to fix this one?

									Pavel

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