From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Anaszewski Subject: Re: [PATCH v2 0/3] led: ledtrig-transient: add support for hrtimer Date: Thu, 14 Sep 2017 22:03:30 +0200 Message-ID: <9bc70fee-40ee-350f-3624-7546b797c64e@gmail.com> References: <20170913175400.42744-1-dtwlin@google.com> <20170913202032.GA30844@amd> <9c75c3a9-4123-c7f3-7725-45ba752d672a@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wr0-f196.google.com ([209.85.128.196]:34585 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751277AbdINUEZ (ORCPT ); Thu, 14 Sep 2017 16:04:25 -0400 In-Reply-To: Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: David Lin Cc: Pavel Machek , Jonathan Corbet , rpurdie@rpsys.net, hdegoede@redhat.com, Greg KH , robh@kernel.org, Rom Lemarchand , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org On 09/14/2017 09:38 PM, David Lin wrote: > On Thu, Sep 14, 2017 at 12:31 PM, Jacek Anaszewski > wrote: >> I would change one more thing in this patch, though. The hr_timer engine >> should be made optional and not used by default for fast LEDs. >> It could be made configurable by exposing additional sysfs file from >> ledtrig-transient.c, e.g. hr_timer_support, accepting boolean value. > > Do you mean in additional to checking the LED_BRIGHTNESS_FAST flag, > userspace has to explicitly enable it via sysfs for ledtrig to select > hrtimer? This seems to be redundant to me. Could you please explain > your concerns and the benefit of doing this? Thanks. My concern is that fast LED users would be automatically imposed a hr_timer overhead, which they may not need. -- Best regards, Jacek Anaszewski