apple-gmux: Add suspend/resume support for the backlight

After S3, the brightness might not be restored to the pre-suspend value.
Request status update calls from the backlight core on suspend/resume to
ensure the brightness value is restored.

Reported-and-tested-by: Austin Lund <austin.lund@gmail.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 8a582bdfdc76..6dcef4f199bb 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -87,6 +87,9 @@ static int gmux_update_status(struct backlight_device *bd)
         struct apple_gmux_data *gmux_data = bl_get_data(bd);
         u32 brightness = bd->props.brightness;
 
+        if (bd->props.state & BL_CORE_SUSPENDED)
+                brightness = 0;
+
         /*
          * Older gmux versions require writing out lower bytes first then
          * setting the upper byte to 0 to flush the values. Newer versions
@@ -102,6 +105,7 @@ static int gmux_update_status(struct backlight_device *bd)
 }
 
 static const struct backlight_ops gmux_bl_ops = {
+        .options = BL_CORE_SUSPENDRESUME,
         .get_brightness = gmux_get_brightness,
         .update_status = gmux_update_status,
 };