asus-wmi: control backlight power through WMI, not ACPI

BugLink: https://bugs.launchpad.net/bugs/1000146

Some h/w that can adjust screen brightness through ACPI functions, but
can't turn on/off the backlight power correctly. So, we list those h/w in
quirks and try to turn on/off the backlight power through WMI.
Signed-off-by: AceLan Kao <acelan.kao@canonical.com>
Signed-off-by: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 556cbb455ed..486f836b79d 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -47,6 +47,9 @@
 #include <linux/thermal.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
+#ifdef CONFIG_ACPI_VIDEO
+#include <acpi/video.h>
+#endif
 
 #include "asus-wmi.h"
 
@@ -1676,7 +1679,13 @@ static int asus_wmi_add(struct platform_device *pdev)
         if (err)
                 goto fail_rfkill;
 
+        if (asus->driver->quirks->wmi_backlight_power)
+                acpi_video_dmi_promote_vendor();
         if (!acpi_video_backlight_support()) {
+#ifdef CONFIG_ACPI_VIDEO
+                pr_info("Disabling ACPI video driver\n");
+                acpi_video_unregister();
+#endif
                 err = asus_wmi_backlight_init(asus);
                 if (err && err != -ENODEV)
                         goto fail_backlight;