linux-kernel - Re: [PATCH] drm/panel: himax-hx83102: Adjust power and gamma to optimize brightness

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Message-ID: <CAHwB_NJJrXQ6aLTO2_eHx5qmEQB9ME5icZUiZmeLQmX6rR-L8A@mail.gmail.com>
Date: Fri, 11 Oct 2024 15:18:36 +0800
From: cong yang <yangcong5@...qin.corp-partner.google.com>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: sam@...nborg.org, neil.armstrong@...aro.org, dianders@...omium.org, 
	airlied@...il.com, simona@...ll.ch, dri-devel@...ts.freedesktop.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/panel: himax-hx83102: Adjust power and gamma to
 optimize brightness

Hi,

Linus Walleij <linus.walleij@...aro.org> 于2024年10月11日周五 15:03写道：
>
> On Fri, Oct 11, 2024 at 4:08 AM Cong Yang
> <yangcong5@...qin.corp-partner.google.com> wrote:
>
> > The current panel brightness is only 360 nit. Adjust the power and gamma to
> > optimize the panel brightness. The brightness after adjustment is 390 nit.
> >
> > Fixes: 3179338750d8 ("drm/panel: Support for IVO t109nw41 MIPI-DSI panel")
> > Signed-off-by: Cong Yang <yangcong5@...qin.corp-partner.google.com>
>
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
>
> If you look in panel-samsung-s6e63m0.c you can see how that driver actually
> uses a set of gamma+power (ACL) settings to regulate the "backlight",
> i.e. the brightness of the OLED display. You might want to implement
> something similar in your driver to actually provide the user with a
> brightness setting.
>
> It's a bit unfortunate that this is for historical reasons called "backlight"
> but the usecase is definitely the same.

Thank you for your suggestion. As far as I know, there are some differences
between OLED panel and our current panel. OLED emits light through the
panel itself.
while the panel we are using now actually drives the LED lights in the
panel through PWM
control of the driver IC.

Usually the brightness is controlled by PWM and exposed to the user space.
Modifying gama here is more about optimizing the gama curve to further improve
the contrast, brightness and detail presentation.

>
> Yours,
> Linus Walleij