This is a note to let you know that I've just added the patch titled
ACPI: video: Don't enable fallback path for creating ACPI backlight by default
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
acpi-video-don-t-enable-fallback-path-for-creating-a.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a85e954e58d67f49abb6fdb79191888ff211d0d2
Author: Mario Limonciello <mario.limonciello@xxxxxxx>
Date: Thu Dec 8 10:42:07 2022 -0600
ACPI: video: Don't enable fallback path for creating ACPI backlight by default
[ 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@xxxxxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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) "
