From 886129a8eebebec260165741fe31421482371006 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 6 May 2014 14:46:23 +0200 Subject: [PATCH] ACPI / video: change acpi-video brightness_switch_enabled default to 0 acpi-video is unique in that it not only generates brightness up/down keypresses, but also (sometimes) actively changes the brightness itself. This presents an inconsistent kernel interface to userspace, basically there are 2 different scenarios, depending on the laptop model: 1) On some laptops a brightness up/down keypress means: show a brightness osd with the current brightness, iow it is a brightness has changed notification. 2) Where as on (a lot of) other laptops it means a brightness up/down key was pressed, deal with it. Most of the desktop environments interpret any press as in scenario 2, and change the brightness up / down as a response to the key events, causing it to be changed twice, once by acpi-video and once by the DE. With the new default for video.use_native_backlight we will be moving even more laptops over to behaving as in scenario 2. Making the remaining laptops even more of a weird exception. Also note that it is hard to detect scenario 1 properly in userspace, and AFAIK none of the DE-s deals with it. Therefor this commit changes the default of brightness_switch_enabled to 0 making its behavior consistent with all the other backlight drivers. Signed-off-by: Hans de Goede Reviewed-by: Aaron Lu Signed-off-by: Rafael J. Wysocki --- Documentation/kernel-parameters.txt | 2 +- drivers/acpi/video.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 43842177b771..cc2c243ac781 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3461,7 +3461,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. the allocated input device; If set to 0, video driver will only send out the event without touching backlight brightness level. - default: 1 + default: 0 virtio_mmio.device= [VMMIO] Memory mapped virtio (platform) device. diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 88393899a0bc..fced27d8e42f 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -68,7 +68,7 @@ MODULE_AUTHOR("Bruno Ducrot"); MODULE_DESCRIPTION("ACPI Video Driver"); MODULE_LICENSE("GPL"); -static bool brightness_switch_enabled = 1; +static bool brightness_switch_enabled; module_param(brightness_switch_enabled, bool, 0644); /* -- 2.20.1