From: Aaron Lu Date: Wed, 11 Mar 2015 14:14:56 +0800 Subject: [PATCH] acpi: video: Allow forcing native backlight on non win8 machines The native backlight behavior (so not registering both the acpi-video and the vendor backlight driver) can be useful on some non win8 machines too, so change the behavior of the video.use_native_backlight=1 or 0 kernel cmdline option to be: if user has set video.use_native_backlight=1 or 0, use that no matter if it is a win8 system or not. Also, we will put some known systems into the DMI table to make them either use native backlight interface or not, and the use_native_backlight_dmi is used to reflect that. Original-by: Hans de Goede Signed-off-by: Aaron Lu Acked-by: Hans de Goede Signed-off-by: Hans de Goede --- drivers/acpi/video.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index db70d550f526..70ea37bea84f 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -82,9 +82,15 @@ module_param(allow_duplicates, bool, 0644); * For Windows 8 systems: used to decide if video module * should skip registering backlight interface of its own. */ -static int use_native_backlight_param = -1; +enum { + NATIVE_BACKLIGHT_NOT_SET = -1, + NATIVE_BACKLIGHT_OFF, + NATIVE_BACKLIGHT_ON, +}; + +static int use_native_backlight_param = NATIVE_BACKLIGHT_NOT_SET; module_param_named(use_native_backlight, use_native_backlight_param, int, 0444); -static bool use_native_backlight_dmi = true; +static int use_native_backlight_dmi = NATIVE_BACKLIGHT_NOT_SET; static int register_count; static struct mutex video_list_lock; @@ -237,15 +243,16 @@ static void acpi_video_switch_brightness(struct work_struct *work); static bool acpi_video_use_native_backlight(void) { - if (use_native_backlight_param != -1) + if (use_native_backlight_param != NATIVE_BACKLIGHT_NOT_SET) return use_native_backlight_param; - else + else if (use_native_backlight_dmi != NATIVE_BACKLIGHT_NOT_SET) return use_native_backlight_dmi; + return acpi_osi_is_win8(); } bool acpi_video_verify_backlight_support(void) { - if (acpi_osi_is_win8() && acpi_video_use_native_backlight() && + if (acpi_video_use_native_backlight() && backlight_device_registered(BACKLIGHT_RAW)) return false; return acpi_video_backlight_support(); @@ -414,7 +421,7 @@ static int __init video_set_bqc_offset(const struct dmi_system_id *d) static int __init video_disable_native_backlight(const struct dmi_system_id *d) { - use_native_backlight_dmi = false; + use_native_backlight_dmi = NATIVE_BACKLIGHT_OFF; return 0; }