asus-laptop: correct error handling in asus_read_brightness()

It is possible that acpi_evaluate_integer might fail and value would not be
set to any value so correct this defect by returning 0 in case of an
error. This is also the correct thing to return because the backlight
subsystem will print the old value of brightness in this case.

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/platform/x86/asus-laptop.c b/drivers/platform/x86/asus-laptop.c
index f2b5d0a8adf0..a4cd78691ac9 100644
--- a/drivers/platform/x86/asus-laptop.c
+++ b/drivers/platform/x86/asus-laptop.c
@@ -775,8 +775,10 @@ static int asus_read_brightness(struct backlight_device *bd)
 
         rv = acpi_evaluate_integer(asus->handle, METHOD_BRIGHTNESS_GET,
                                    NULL, &value);
-        if (ACPI_FAILURE(rv))
+        if (ACPI_FAILURE(rv)) {
                 pr_warn("Error reading brightness\n");
+                return 0;
+        }
 
         return value;
 }