From: Hans de Goede hdegoede@redhat.com
[ Upstream commit a5df42521f328b45c9d89c13740e747be08ac66e ]
Simplify __acpi_video_get_backlight_type() removing a nested if which makes the flow harder to follow.
This also results in having only 1 exit point with return acpi_backlight_native instead of 2.
Note this drops the (video_caps & ACPI_VIDEO_BACKLIGHT) check from the if (acpi_osi_is_win8() && native_available) return native path. Windows 8's hardware certification requirements include that there must be ACPI video bus backlight control, so the ACPI_VIDEO_BACKLIGHT check is redundant.
Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/acpi/video_detect.c | 36 +++++++++++++++++------------------- 1 file changed, 17 insertions(+), 19 deletions(-)
diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index 13f10fbcd7f0..0c17ee93f861 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -734,6 +734,16 @@ static bool google_cros_ec_present(void) return acpi_dev_found("GOOG0004") || acpi_dev_found("GOOG000C"); }
+/* + * Windows 8 and newer no longer use the ACPI video interface, so it often + * does not work. So on win8+ systems prefer native brightness control. + * Chromebooks should always prefer native backlight control. + */ +static bool prefer_native_over_acpi_video(void) +{ + return acpi_osi_is_win8() || google_cros_ec_present(); +} + /* * Determine which type of backlight interface to use on this system, * First check cmdline, then dmi quirks, then do autodetect. @@ -779,26 +789,14 @@ static enum acpi_backlight_type __acpi_video_get_backlight_type(bool native) if (apple_gmux_backlight_present()) return acpi_backlight_apple_gmux;
- /* Chromebooks should always prefer native backlight control. */ - if (google_cros_ec_present() && native_available) - return acpi_backlight_native; + /* Use ACPI video if available, except when native should be preferred. */ + if ((video_caps & ACPI_VIDEO_BACKLIGHT) && + !(native_available && prefer_native_over_acpi_video())) + return acpi_backlight_video;
- /* On systems with ACPI video use either native or ACPI video. */ - if (video_caps & ACPI_VIDEO_BACKLIGHT) { - /* - * Windows 8 and newer no longer use the ACPI video interface, - * so it often does not work. If the ACPI tables are written - * for win8 and native brightness ctl is available, use that. - * - * The native check deliberately is inside the if acpi-video - * block on older devices without acpi-video support native - * is usually not the best choice. - */ - if (acpi_osi_is_win8() && native_available) - return acpi_backlight_native; - else - return acpi_backlight_video; - } + /* Use native if available */ + if (native_available && prefer_native_over_acpi_video()) + return acpi_backlight_native;
/* No ACPI video (old hw), use vendor specific fw methods. */ return acpi_backlight_vendor;