From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 644C8C0650F for ; Mon, 5 Aug 2019 10:37:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3321D20679 for ; Mon, 5 Aug 2019 10:37:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="SdYRFXoz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728393AbfHEKh4 (ORCPT ); Mon, 5 Aug 2019 06:37:56 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:55200 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727349AbfHEKhz (ORCPT ); Mon, 5 Aug 2019 06:37:55 -0400 Received: by mail-wm1-f68.google.com with SMTP id p74so74197963wme.4 for ; Mon, 05 Aug 2019 03:37:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=EjSGNU5tuMFasj89k5pfoAkxeWuwm7YGZxI63pDJurY=; b=SdYRFXozELsThSHXdS1mXooull3R6J9nnf8C9J4LG2rf8Ay/tHpcXw2sFKAZoIllXB UKzi8TW1M0OqDdoMJIDgbNPtrLtVsqGNe/0mrOegp1PJbxsi91tSM2AMp05i+GQJGWfv 0ndxMSUXoF6zD4BAG4BkQVA5ggAsEF1fWdZLuxRZwHQxF2mE9tNSwMUHD6NPuvpOd/pG t6FqshJ99YgzsFLuWKobI7n04sKxA23fNY0aWKPCmWnE/D5C39GPb0eyMHtNpKwaD/mJ 4ho5THOfnm4/3mlbtxwCfPSP8ZB7VdziBnItzlaaDFyKQ7bhlLHbMKVB7phZr+csRiRE XmCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=EjSGNU5tuMFasj89k5pfoAkxeWuwm7YGZxI63pDJurY=; b=apGVaYONhH+9sKzMGCEnnYZNNNVxEYdTaOoR9xgLUgwR61vruxXsUGTKeAG5z+GwH9 RVUvcAuFdSligtIQhly6RV9bDL5svaAiVTxNCdxN0NGY6q9DyzAlE3And6beWNCwg83O Hny+BXWYJ+szFUb1deuvHmdSuPNeOdvt/X4cbHhEKeIzZNSnpfxxAmnsGeGb82okWfdL bH28F6ynC+2Xfy1mRbPrWE5WONmXTGpMVrFwfv4NNtR3tt4Lhd8whSM9BsORVJYmnIgq qAIQ67Pw+zHNvTN7RAAOQju+mdvwGOrbvdgmeRDFOmsSuHFM+lJaXMJy4j5u1uYPvNrd SKfw== X-Gm-Message-State: APjAAAU0+rA8vk/DIeHI9Ji1XZ42+sQ4aaw/r7/gd32wOBI7x39VIetw z4YS7o3rdZ/1TdDgLZVoGuRprQ== X-Google-Smtp-Source: APXvYqyfPy8bJ4jliIHsN8Aii8j0f6KsqZMMACwhVIeHmj6Cf501bv9kzRahA7ZUnqifBzzHRD/S/w== X-Received: by 2002:a1c:cfc3:: with SMTP id f186mr17103441wmg.134.1565001472966; Mon, 05 Aug 2019 03:37:52 -0700 (PDT) Received: from dell ([109.180.115.177]) by smtp.gmail.com with ESMTPSA id o11sm79528209wmh.37.2019.08.05.03.37.51 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 05 Aug 2019 03:37:52 -0700 (PDT) Date: Mon, 5 Aug 2019 11:37:50 +0100 From: Lee Jones To: Matthias Kaehlcke Cc: Thierry Reding , Daniel Thompson , Jingoo Han , Bartlomiej Zolnierkiewicz , linux-pwm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, Enric Balletbo i Serra , Douglas Anderson , Brian Norris , Pavel Machek , Jacek Anaszewski Subject: Re: [PATCH v3 0/4] backlight: Expose brightness curve type through sysfs Message-ID: <20190805103750.GG4739@dell> References: <20190709190007.91260-1-mka@chromium.org> <20190722235926.GA250418@google.com> <20190725111541.GA23883@dell> <20190725171726.GD250418@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190725171726.GD250418@google.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 Jul 2019, Matthias Kaehlcke wrote: > On Thu, Jul 25, 2019 at 12:15:41PM +0100, Lee Jones wrote: > > On Mon, 22 Jul 2019, Matthias Kaehlcke wrote: > > > > > On Tue, Jul 09, 2019 at 12:00:03PM -0700, Matthias Kaehlcke wrote: > > > > Backlight brightness curves can have different shapes. The two main > > > > types are linear and non-linear curves. The human eye doesn't > > > > perceive linearly increasing/decreasing brightness as linear (see > > > > also 88ba95bedb79 "backlight: pwm_bl: Compute brightness of LED > > > > linearly to human eye"), hence many backlights use non-linear (often > > > > logarithmic) brightness curves. The type of curve is currently opaque > > > > to userspace, so userspace often relies on more or less reliable > > > > heuristics (like the number of brightness levels) to decide whether > > > > to treat a backlight device as linear or non-linear. > > > > > > > > Export the type of the brightness curve via a new sysfs attribute. > > > > > > > > Matthias Kaehlcke (4): > > > > MAINTAINERS: Add entry for stable backlight sysfs ABI documentation > > > > backlight: Expose brightness curve type through sysfs > > > > backlight: pwm_bl: Set scale type for CIE 1931 curves > > > > backlight: pwm_bl: Set scale type for brightness curves specified in > > > > the DT > > > > > > > > .../ABI/testing/sysfs-class-backlight | 26 ++++++++++++++ > > > > MAINTAINERS | 2 ++ > > > > drivers/video/backlight/backlight.c | 19 ++++++++++ > > > > drivers/video/backlight/pwm_bl.c | 35 ++++++++++++++++++- > > > > include/linux/backlight.h | 8 +++++ > > > > 5 files changed, 89 insertions(+), 1 deletion(-) > > > > create mode 100644 Documentation/ABI/testing/sysfs-class-backlight > > > > > > ping, any comments on v3? > > > > Looks like PATCH 2/4 still needs seeing to. > > The patch currently doesn't have any comments. > > Do you see any specific things that need improvement? If so, could you > comment on the patch? It needs Daniel T's Ack. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Date: Mon, 05 Aug 2019 10:37:50 +0000 Subject: Re: [PATCH v3 0/4] backlight: Expose brightness curve type through sysfs Message-Id: <20190805103750.GG4739@dell> List-Id: References: <20190709190007.91260-1-mka@chromium.org> <20190722235926.GA250418@google.com> <20190725111541.GA23883@dell> <20190725171726.GD250418@google.com> In-Reply-To: <20190725171726.GD250418@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Matthias Kaehlcke Cc: Thierry Reding , Daniel Thompson , Jingoo Han , Bartlomiej Zolnierkiewicz , linux-pwm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, Enric Balletbo i Serra , Douglas Anderson , Brian Norris , Pavel Machek , Jacek Anaszewski On Thu, 25 Jul 2019, Matthias Kaehlcke wrote: > On Thu, Jul 25, 2019 at 12:15:41PM +0100, Lee Jones wrote: > > On Mon, 22 Jul 2019, Matthias Kaehlcke wrote: > > > > > On Tue, Jul 09, 2019 at 12:00:03PM -0700, Matthias Kaehlcke wrote: > > > > Backlight brightness curves can have different shapes. The two main > > > > types are linear and non-linear curves. The human eye doesn't > > > > perceive linearly increasing/decreasing brightness as linear (see > > > > also 88ba95bedb79 "backlight: pwm_bl: Compute brightness of LED > > > > linearly to human eye"), hence many backlights use non-linear (often > > > > logarithmic) brightness curves. The type of curve is currently opaque > > > > to userspace, so userspace often relies on more or less reliable > > > > heuristics (like the number of brightness levels) to decide whether > > > > to treat a backlight device as linear or non-linear. > > > > > > > > Export the type of the brightness curve via a new sysfs attribute. > > > > > > > > Matthias Kaehlcke (4): > > > > MAINTAINERS: Add entry for stable backlight sysfs ABI documentation > > > > backlight: Expose brightness curve type through sysfs > > > > backlight: pwm_bl: Set scale type for CIE 1931 curves > > > > backlight: pwm_bl: Set scale type for brightness curves specified in > > > > the DT > > > > > > > > .../ABI/testing/sysfs-class-backlight | 26 ++++++++++++++ > > > > MAINTAINERS | 2 ++ > > > > drivers/video/backlight/backlight.c | 19 ++++++++++ > > > > drivers/video/backlight/pwm_bl.c | 35 ++++++++++++++++++- > > > > include/linux/backlight.h | 8 +++++ > > > > 5 files changed, 89 insertions(+), 1 deletion(-) > > > > create mode 100644 Documentation/ABI/testing/sysfs-class-backlight > > > > > > ping, any comments on v3? > > > > Looks like PATCH 2/4 still needs seeing to. > > The patch currently doesn't have any comments. > > Do you see any specific things that need improvement? If so, could you > comment on the patch? It needs Daniel T's Ack. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog