linux-kernel - [PATCH 1/2] platform/loongarch: laptop: Get brightness setting from EC on probe

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250531113851.21426-2-ziyao@disroot.org>
Date: Sat, 31 May 2025 11:38:50 +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>,
	stable@...r.kernel.org
Subject: [PATCH 1/2] platform/loongarch: laptop: Get brightness setting from EC on probe

Previously 1 is unconditionally taken as current brightness value. This
causes problems since it's required to restore brightness settings on
resumption, and a value that doesn't match EC's state before suspension
will cause surprising changes of screen brightness.

Let's get brightness from EC and take it as the current brightness on
probe of the laptop driver to avoid the surprising behavior. Tested on
TongFang L860-T2 3A5000 laptop.

Cc: stable@...r.kernel.org
Fixes: 6246ed09111f ("LoongArch: Add ACPI-based generic laptop driver")
Signed-off-by: Yao Zi <ziyao@...root.org>
---
 drivers/platform/loongarch/loongson-laptop.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/loongarch/loongson-laptop.c b/drivers/platform/loongarch/loongson-laptop.c
index 99203584949d..828bd62e3596 100644
--- a/drivers/platform/loongarch/loongson-laptop.c
+++ b/drivers/platform/loongarch/loongson-laptop.c
@@ -392,7 +392,7 @@ static int laptop_backlight_register(void)
 	if (!acpi_evalf(hotkey_handle, &status, "ECLL", "d"))
 		return -EIO;
 
-	props.brightness = 1;
+	props.brightness = ec_get_brightness();
 	props.max_brightness = status;
 	props.type = BACKLIGHT_PLATFORM;
 
-- 
2.49.0