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From: David Lin <dtwlin@google.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Jonathan Corbet <corbet@lwn.net>,
	rpurdie@rpsys.net, Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	hdegoede@redhat.com, Greg KH <gregkh@linuxfoundation.org>,
	robh@kernel.org, Rom Lemarchand <romlem@google.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-leds@vger.kernel.org
Subject: Re: [PATCH v2 0/3] led: ledtrig-transient: add support for hrtimer
Date: Thu, 14 Sep 2017 10:31:41 -0700	[thread overview]
Message-ID: <CAPzFB+XrhAUE3Qd+bicCCPk6V7xq7BV=90y=KXudZmGDaS2+cA@mail.gmail.com> (raw)
In-Reply-To: <20170913213424.GA2493@amd>

On Wed, Sep 13, 2017 at 2:34 PM, Pavel Machek <pavel@ucw.cz> wrote:
>
> On Wed 2017-09-13 14:20:58, David Lin wrote:
> > On Wed, Sep 13, 2017 at 1:20 PM, Pavel Machek <pavel@ucw.cz> wrote:
> > >
> > > Hi!
> > >
> > > > These patch series add the LED_BRIGHTNESS_FAST flag support for
> > > > ledtrig-transient to use hrtimer so that platforms with high-resolution timer
> > > > support can have better accuracy in the trigger duration timing. The need for
> > > > this support is driven by the fact that Android has removed the timed_ouput [1]
> > > > and is now using led-trigger for handling vibrator control which requires the
> > > > timer to be accurate up to a millisecond. However, this flag support would also
> > > > allow hrtimer to co-exist with the ktimer without causing warning to the
> > > > existing drivers [2].
> > >
> > > NAK.
> > >
> > > LEDs do not need extra overhead, and vibrator control should not go
> > > through LED subsystem.
> > >
> > > Input subsystem includes support for vibrations and force
> > > feedback. Please use that instead.
> >
> > I thought we are already over this discussion. As of now, the support
> > of vibrator through ledtrig is documented
> > (Documentation/leds/ledtrig-transient.txt) and there are users using
> > it.
>
> I also thought we are over with that discussion.
>
> Yes, I'm working on fixing the docs.
>
> What mainline users are doing that?

Please refer to patch:
https://patchwork.kernel.org/patch/8664831/ and
https://android.googlesource.com/platform%2Fhardware%2Flibhardware/+/61701df363310a5cbd95e3e1638baa9526e42c9b

I don't think currently there are drivers in the mainline using it
yet, the reason being most of the Android devices are still on 4.4
kernel which still uses the legacy timed_output device.

  reply	other threads:[~2017-09-14 17:31 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-13 17:53 [PATCH v2 0/3] led: ledtrig-transient: add support for hrtimer David Lin
2017-09-13 17:53 ` [PATCH v2 1/3] leds: Replace flags bit shift with BIT() macros David Lin
2017-09-14 19:43   ` Jacek Anaszewski
2017-09-13 17:53 ` [PATCH v2 2/3] leds: Add the LED_BRIGHTNESS_FAST flag David Lin
2017-09-13 17:54 ` [PATCH v2 3/3] led: ledtrig-transient: add support for hrtimer David Lin
2017-09-13 20:20 ` [PATCH v2 0/3] " Pavel Machek
2017-09-13 21:20   ` David Lin
2017-09-13 21:34     ` Pavel Machek
2017-09-14 17:31       ` David Lin [this message]
2017-09-14 19:42         ` Pavel Machek
2017-09-14 19:31   ` Jacek Anaszewski
2017-09-14 19:38     ` David Lin
2017-09-14 20:03       ` Jacek Anaszewski
2017-09-14 20:58     ` Vibrations in input vs. LED was " Pavel Machek
2017-09-15 18:34       ` Dmitry Torokhov
2017-09-15 21:55         ` Jacek Anaszewski
2017-09-15 22:30           ` Dmitry Torokhov
2017-09-17 16:41             ` Jacek Anaszewski
2017-09-17 18:22               ` Pavel Machek
2017-09-17 21:15                 ` Pavel Machek
2017-09-18 20:50                 ` Jacek Anaszewski
2017-09-18 22:29                   ` Dmitry Torokhov
2017-09-19 20:45                     ` Jacek Anaszewski
2017-09-19 21:07                       ` Dmitry Torokhov
2017-09-20 19:31                         ` Jacek Anaszewski
2017-09-20 11:29                       ` Pavel Machek
2017-09-20 20:08                         ` Jacek Anaszewski
2017-10-06 11:48                           ` Pavel Machek
2017-10-06 20:57                             ` Jacek Anaszewski
2017-09-20 11:26                   ` Pavel Machek
2017-09-28  5:03             ` David Lin
2017-09-28  5:43               ` Dmitry Torokhov
2017-09-28 19:22                 ` David Lin
2017-10-05  0:40                   ` Dmitry Torokhov
2017-09-16 12:59           ` Pavel Machek
2017-09-15 21:55       ` Jacek Anaszewski
2017-09-16  1:58         ` Pavel Machek
2017-09-17 16:41           ` Jacek Anaszewski
2017-09-17 17:50             ` Pavel Machek
2017-09-18 20:43               ` Jacek Anaszewski
2017-09-20 11:15                 ` Pavel Machek
2017-09-20 18:44                   ` Jacek Anaszewski

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