linux-kernel - [PATCH v2 0/2] Backlight control improvements for loongson

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Message-ID: <20250605054828.15093-1-ziyao@disroot.org>
Date: Thu,  5 Jun 2025 05:48:26 +0000
From: Yao Zi <ziyao@...root.org>
To: Huacai Chen <chenhuacai@...nel.org>,
	Jianmin Lv <lvjianmin@...ngson.cn>,
	WANG Xuerui <kernel@...0n.name>
Cc: linux-kernel@...r.kernel.org,
	loongarch@...ts.linux.dev,
	Mingcong Bai <jeffbai@...c.io>,
	Kexy Biscuit <kexybiscuit@...c.io>,
	Yao Zi <ziyao@...root.org>
Subject: [PATCH v2 0/2] Backlight control improvements for loongson_laptop

I've observed strange screen brightness changes on TongFang L860-T2
3A5000 laptop after resumption. It's found that a brightness value that
doesn't match the hardware state before suspension is "restored" for the
EC, causing the strange behavior.

This series fixes the behavior by obtaining EC's brightness setting
instead of using a constant as current brightness on probe.

While digging through the code, I've found some unused,
power-control-related functions in the driver. They're cleaned up and
used to support power control of backlight in the second patch as well.

Changed from v1:
- Reword commit message of PATCH 1
- PATCH 2
  - Always issue a power-on command on probe to ensure the backlight has
    been powered, matching our expectation
  - Cache backlight state in the driver to reduce interaction with EC
- Link to v1: https://lore.kernel.org/loongarch/20250531113851.21426-1-ziyao@disroot.org/

Yao Zi (2):
  platform/loongarch: laptop: Get brightness setting from EC on probe
  platform/loongarch: laptop: Support backlight power control

 drivers/platform/loongarch/loongson-laptop.c | 78 ++++++++++----------
 1 file changed, 39 insertions(+), 39 deletions(-)

-- 
2.49.0