From: Daniel Thompson <danielt@kernel.org>
To: Michael Grzeschik <m.grzeschik@pengutronix.de>
Cc: "Uwe Kleine-König" <ukleinek@kernel.org>,
"Lee Jones" <lee@kernel.org>, "Jingoo Han" <jingoohan1@gmail.com>,
"Helge Deller" <deller@gmx.de>,
Pengutronix <kernel@pengutronix.de>,
linux-pwm@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] backlight: pwm_bl: apply the initial backlight state with sane defaults
Date: Thu, 30 Oct 2025 11:51:07 +0000 [thread overview]
Message-ID: <aQNRK5ksNDMMve0x@aspen.lan> (raw)
In-Reply-To: <20250731-blpwm-v1-1-0171fd31bff9@pengutronix.de>
On Thu, Jul 31, 2025 at 10:47:18AM +0200, Michael Grzeschik wrote:
> Currently when calling pwm_apply_might_sleep in the probe routine
> the pwm will be configured with an not fully defined state.
>
> The duty_cycle is not yet set in that moment. There is a final
> backlight_update_status call that will have a properly setup state.
> However this change in the backlight can create a short flicker if the
> backlight was already preinitialised.
>
> We fix the flicker by moving the pwm_apply after the default duty_cycle
> can be calculated.
>
> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Daniel.
next prev parent reply other threads:[~2025-10-30 11:50 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-31 8:47 [PATCH] backlight: pwm_bl: apply the initial backlight state with sane defaults Michael Grzeschik
2025-08-01 6:32 ` Uwe Kleine-König
2025-09-09 13:49 ` Uwe Kleine-König
2025-09-10 7:33 ` Michael Grzeschik
2025-10-30 11:51 ` Daniel Thompson [this message]
2025-11-07 8:00 ` Uwe Kleine-König
2025-11-07 14:51 ` Daniel Thompson
2025-11-07 15:48 ` Michael Grzeschik
2025-11-06 16:59 ` (subset) " Lee Jones
2025-11-14 14:09 ` Mark Brown
2025-11-18 12:52 ` Daniel Thompson
2025-11-25 8:24 ` Michael Grzeschik
2025-11-25 11:34 ` Daniel Thompson
2025-11-25 12:36 ` Mark Brown
2025-11-25 12:54 ` Lee Jones
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