backlight: don't resume backlight for dark resume

For an idle suspend, we set the resume backlight sysfs file which is used during
resume in the kernel. This causes the screen to flash on for a moment during a
dark resume. This change prevents the backlight resume from doing anything
during a dark resume.

BUG=chrome-os-partner:9812
TEST=idle suspend system with dark resume (see backlight doesn't turn on)

Change-Id: Iccd02b99bdd682853fc9b184817c4d43028afcf6
Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/45824
Reviewed-by: Sameer Nanda <snanda@chromium.org>

diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 49af059..45ed629 100644 (file)
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -260,7 +260,13 @@ static int backlight_suspend(struct device *dev, pm_message_t state)
 
 static int backlight_resume(struct device *dev)
 {
-       struct backlight_device *bd = to_backlight_device(dev);
+       struct backlight_device *bd;
+
+       if (dpm_is_dark_resume()) {
+               dev_info(dev, "disabled for dark resume\n");
+               return 0;
+       }
+       bd = to_backlight_device(dev);
 
        mutex_lock(&bd->ops_lock);
        if ((bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) ||