From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH v4 02/20] backlight: add backlight_is_blank() Date: Tue, 7 Jul 2020 07:42:16 +0200 Message-ID: <20200707054216.GE3278063@phenom.ffwll.local> References: <20200703184546.144664-1-sam@ravnborg.org> <20200703184546.144664-3-sam@ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727928AbgGGFmV (ORCPT ); Tue, 7 Jul 2020 01:42:21 -0400 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56A3FC061794 for ; Mon, 6 Jul 2020 22:42:21 -0700 (PDT) Received: by mail-wm1-x342.google.com with SMTP id a6so934058wmm.0 for ; Mon, 06 Jul 2020 22:42:21 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20200703184546.144664-3-sam@ravnborg.org> Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Sam Ravnborg Cc: dri-devel@lists.freedesktop.org, Jingoo Han , Lee Jones , Daniel Thompson , Andy Gross , Bartlomiej Zolnierkiewicz , Bjorn Andersson , Daniel Vetter , David Airlie , Emil Velikov , Jonathan Corbet , linux-arm-msm@vger.kernel.org, linux-pwm@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Michael Hennerich , patches@opensource.cirrus.com, Support Opensource , Thierry Reding , Thomas On Fri, Jul 03, 2020 at 08:45:28PM +0200, Sam Ravnborg wrote: > The backlight support has two properties that express the state: > - power > - state Tiny nit, but please add "fb_blank" here too, commit message doesn't match the code anymore. With that: Reviewed-by: Daniel Vetter > > It is un-documented and easy to get wrong. > Add backlight_is_blank() helper to make it simpler > for drivers to get the check of the state correct. > > A lot of drivers also includes checks for fb_blank. > This check is redundant when the state is checked > and thus not needed in this helper function. > But added anyway to avoid introducing subtle bugs > due to the creative use of fb_blank in some drivers. > Introducing this helper will for some drivers results in > added support for fb_blank. This will be a change in > functionality, which will improve the backlight driver. > > Rolling out this helper to all relevant backlight drivers > will eliminate almost all accesses to fb_blank. > > v4: > - struct backlight_device * is now const > > v3: > - Clarified that the fb_blank support in > backlight_is_blank() may result in functionality > changes for the users (Emil) > > v2: > - Added fb_blank condition (Daniel) > > Signed-off-by: Sam Ravnborg > Reviewed-by: Daniel Thompson > Reviewed-by: Peter Ujfalusi > Reviewed-by: Emil Velikov > Cc: Emil Velikov > Cc: Daniel Vetter > Cc: Lee Jones > Cc: Daniel Thompson > Cc: Jingoo Han > --- > include/linux/backlight.h | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/include/linux/backlight.h b/include/linux/backlight.h > index 56e4580d4f55..56e51ebab740 100644 > --- a/include/linux/backlight.h > +++ b/include/linux/backlight.h > @@ -175,6 +175,25 @@ static inline void backlight_put(struct backlight_device *bd) > put_device(&bd->dev); > } > > +/** > + * backlight_is_blank - Return true if display is expected to be blank > + * @bd: the backlight device > + * > + * Display is expected to be blank if any of these is true:: > + * > + * 1) if power in not UNBLANK > + * 2) if fb_blank is not UNBLANK > + * 3) if state indicate BLANK or SUSPENDED > + * > + * Returns true if display is expected to be blank, false otherwise. > + */ > +static inline bool backlight_is_blank(const struct backlight_device *bd) > +{ > + return bd->props.power != FB_BLANK_UNBLANK || > + bd->props.fb_blank != FB_BLANK_UNBLANK || > + bd->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK); > +} > + > extern struct backlight_device *backlight_device_register(const char *name, > struct device *dev, void *devdata, const struct backlight_ops *ops, > const struct backlight_properties *props); > -- > 2.25.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch