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[80.7.220.175]) by smtp.gmail.com with ESMTPSA id b9sm16533947wrh.81.2021.07.12.03.25.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jul 2021 03:25:55 -0700 (PDT) Date: Mon, 12 Jul 2021 11:25:53 +0100 From: Daniel Thompson To: Noralf =?utf-8?Q?Tr=C3=B8nnes?= Cc: Marek Vasut , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, Meghana Madhyastha , Sean Paul , Thierry Reding Subject: Re: [PATCH] video: backlight: Drop maximum brightness override for brightness zero Message-ID: <20210712102553.ehsgp2ozrveuwaxv@maple.lan> References: <20210709132600.5417-1-marex@denx.de> <0822c219-c1c6-0bb4-f379-e73f40adfa8e@tronnes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0822c219-c1c6-0bb4-f379-e73f40adfa8e@tronnes.org> Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Fri, Jul 09, 2021 at 03:53:16PM +0200, Noralf Trønnes wrote: > > > Den 09.07.2021 15.26, skrev Marek Vasut: > > The note in c2adda27d202f ("video: backlight: Add of_find_backlight helper > > in backlight.c") says that gpio-backlight uses brightness as power state. > > This has been fixed since in ec665b756e6f7 ("backlight: gpio-backlight: > > Correct initial power state handling") and other backlight drivers do not > > require this workaround. Drop the workaround. > > > > This fixes the case where e.g. pwm-backlight can perfectly well be set to > > brightness 0 on boot in DT, which without this patch leads to the display > > brightness to be max instead of off. > > > > Fixes: c2adda27d202f ("video: backlight: Add of_find_backlight helper in backlight.c") > > I not sure about the rules, but if this is automatically picked up for > stable, maybe this is needed to avoid changing behaviour on 4.19: > > > of_find_backlight() was added in 4.17 and the gpio fix in 5.4. > > Or perhaps there are other ways to signal this dependency. Agree we need to make sure the Fixes: tag doesn't provoke regressions in v4.19. Is this the syntax appropriate? Cc: # 5.4+ Cc: # 4.19.x: ec665b756e6f7: backlight: gpio-backlight: Correct initial power state handling > > Signed-off-by: Marek Vasut > > Cc: Daniel Thompson > > Cc: Meghana Madhyastha > > Cc: Noralf Trønnes > > Cc: Sean Paul > > Cc: Thierry Reding > > --- > > Acked-by: Noralf Trønnes With the above (or something similar to avoid problems with v4.19): Reviewed-by: Daniel Thompson Daniel.