linux-kernel - [PATCH AUTOSEL 6.1 05/10] ACPI: video: Don't enable fallback path for creating ACPI backlight by default

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: <20230103183934.2022663-5-sashal@kernel.org>
Date:   Tue,  3 Jan 2023 13:39:29 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Mario Limonciello <mario.limonciello@....com>,
        Hans de Goede <hdegoede@...hat.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>, rafael@...nel.org,
        linux-acpi@...r.kernel.org
Subject: [PATCH AUTOSEL 6.1 05/10] ACPI: video: Don't enable fallback path for creating ACPI backlight by default

From: Mario Limonciello <mario.limonciello@....com>

[ Upstream commit 5aa9d943e9b6bf6e6023645cbe7ce7d5ed84baf4 ]

The ACPI video detection code has a module parameter
`register_backlight_delay` which is currently configured to 8 seconds.
This means that if after 8 seconds of booting no native driver has created
a backlight device then the code will attempt to make an ACPI video
backlight device.

This was intended as a safety mechanism with the backlight overhaul that
occurred in kernel 6.1, but as it doesn't appear necesssary set it to be
disabled by default.

Suggested-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
Reviewed-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/acpi/acpi_video.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index f64fdb029090..0c79f463fbfd 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -70,11 +70,7 @@ module_param(device_id_scheme, bool, 0444);
 static int only_lcd = -1;
 module_param(only_lcd, int, 0444);
 
-/*
- * Display probing is known to take up to 5 seconds, so delay the fallback
- * backlight registration by 5 seconds + 3 seconds for some extra margin.
- */
-static int register_backlight_delay = 8;
+static int register_backlight_delay;
 module_param(register_backlight_delay, int, 0444);
 MODULE_PARM_DESC(register_backlight_delay,
 	"Delay in seconds before doing fallback (non GPU driver triggered) "
-- 
2.35.1