From: Yao Zi <me@ziyao.cc>
To: Zixing Liu <liushuyu@aosc.io>,
linux-kernel@vger.kernel.org, Yao Zi <ziyao@disroot.org>,
Jianmin Lv <lvjianmin@loongson.cn>,
WANG Xuerui <kernel@xen0n.name>,
Huacai Chen <chenhuacai@kernel.org>
Cc: Kexy Biscuit <kexybiscuit@aosc.io>,
Mingcong Bai <jeffbai@aosc.io>,
loongarch@lists.linux.dev, stable@vger.kernel.org,
Yao Zi <me@ziyao.cc>
Subject: Re: [PATCH v2] platform/loongarch: laptop: explicitly reset the bl_powered state when resuming
Date: Sat, 25 Jul 2026 17:35:57 +0000 [thread overview]
Message-ID: <amTz4qZ6CE7fn7QS@pie> (raw)
In-Reply-To: <20260723121840.1120953-2-liushuyu@aosc.io>
On Thu, Jul 23, 2026 at 08:18:39PM +0800, Zixing Liu wrote:
> On EAECIS NL60R with EC firmware version 1.11, resuming from S3 has a very
> high chance (>= 90%) of causing the EC to lose the previous backlight
> power state. When this happens, the laptop resumes normally from S3, but
> the backlight remains off (when shining on the screen with a flash light,
> we can see the screen contents are updating normally).
>
> Since there is no generic way to query the EC's backlight state on
> Loongson laptop platforms, assume the worst-case scenario and restart the
> backlight power inside the kernel each time the system resumes.
>
> Cc: stable@vger.kernel.org
> Fixes: 53c762b47f72 ("platform/loongarch: laptop: Add backlight power control support")
> Signed-off-by: Zixing Liu <liushuyu@aosc.io>
> ---
> Changes in v2:
> - Move bl_powered reset logic to loongson_hotkey_suspend.
> - Link to v1: https://lore.kernel.org/loongarch/20260722044457.1333404-1-liushuyu@aosc.io/
Again on my TongFang L860-T2 3A5000 laptop, no regression is observed.
Tested-by: Yao Zi <me@ziyao.cc>
Best regards.
Yao Zi
prev parent reply other threads:[~2026-07-25 17:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-23 12:18 [PATCH v2] platform/loongarch: laptop: explicitly reset the bl_powered state when resuming Zixing Liu
2026-07-23 12:57 ` Xi Ruoyao
2026-07-25 17:35 ` Yao Zi [this message]
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