From: Marek Vasut <email@example.com> To: Daniel Thompson <firstname.lastname@example.org> Cc: email@example.com, firstname.lastname@example.org, "Meghana Madhyastha" <email@example.com>, "Noralf Trønnes" <firstname.lastname@example.org>, "Sean Paul" <email@example.com>, "Thierry Reding" <firstname.lastname@example.org> Subject: Re: [PATCH] video: backlight: Only set maximum brightness for gpio-backlight Date: Fri, 9 Jul 2021 15:19:47 +0200 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <firstname.lastname@example.org> On 7/9/21 1:03 PM, Daniel Thompson wrote: > On Thu, Jul 08, 2021 at 11:10:58AM +0200, Marek Vasut wrote: >> The note in c2adda27d202f ("video: backlight: Add of_find_backlight helper >> in backlight.c") says that gpio-backlight uses brightness as power state. >> Other backlight drivers do not, so limit this workaround to gpio-backlight. >> >> 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") >> Signed-off-by: Marek Vasut <email@example.com> >> Cc: Daniel Thompson <firstname.lastname@example.org> >> Cc: Meghana Madhyastha <email@example.com> >> Cc: Noralf Trønnes <firstname.lastname@example.org> >> Cc: Sean Paul <email@example.com> >> Cc: Thierry Reding <firstname.lastname@example.org> > > I have to admit that this patch really does makes it clear just how > nasty the hack in of_find_backlight() currently is. > > Moreover I think it is also be obsolete. gpio-backlight power mode > handling was pretty broken when this code was introduced. It was fixed > in 2019 by ec665b756e6f ("backlight: gpio backlight: Correct initial > power state handling") by trying to match the behaviour of PWM > backlight. The new code always sets the brightness to 1 so I think we > can just remove the hack from of_find_backlight() since I think it is > unreachable. I assume by "new code" you mean the fixed gpio-backlight driver ? Dropping the whole code after the Note: is fine by me.
next prev parent reply other threads:[~2021-07-09 13:20 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-08 9:10 Marek Vasut 2021-07-09 11:03 ` Daniel Thompson 2021-07-09 13:19 ` Marek Vasut [this message] 2021-07-09 13:25 ` Noralf Trønnes
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