On 04/27/2017 05:48 AM, David Lin wrote: > On Tue, Apr 25, 2017 at 1:15 PM, Jacek Anaszewski > <jacek.anaszewski@xxxxxxxxx> wrote: >>> However, there's a need to >>> support hrtimer if the LED subsystem claims support the use case of >>> vibrator (please see Documentation/leds/ledtrig-transient.txt) as even >>> a 5ms of variation is perceivable to the user. I'm thinking if a >>> better interim solution is to introduce a >>> LEDS_TRIGGER_TRANSIENT_HRTIMER config to work with both timers in >>> compile time. Would you agree? >> >> I think that it would be better if LED class driver set a flag >> marking itself as capable of setting brightness with high rate. >> I'd limit that only to leds-gpio and devices driven through >> memory mapped registers. >> >> Having the flag e.g. LED_BRIGHTNESS_FAST, we could add support for >> hr timers also to ledtrig-timer. > > Can I resubmit the patch implementing LED_BRIGHTNESS_FAST using hrtimer? Yeah, but please split the changes into two patches: 1/2 - addition of a flag to linux/leds.h and corresponding update of Documentation/leds/leds-class.txt 2/2 - addition of hr timer support to ledtrig-transient.c -- Best regards, Jacek Anaszewski