linux-kernel - [PATCH] asus-laptop: correct error handling in asus_read

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Message-Id: <1460766432-5390-1-git-send-email-giedrius.statkevicius@gmail.com>
Date:	Sat, 16 Apr 2016 03:27:12 +0300
From:	Giedrius Statkevičius 
	<giedrius.statkevicius@...il.com>
To:	corentin.chary@...il.com, dvhart@...radead.org
Cc:	acpi4asus-user@...ts.sourceforge.net,
	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
	Giedrius Statkevičius 
	<giedrius.statkevicius@...il.com>
Subject: [PATCH] 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@...il.com>
---
 drivers/platform/x86/asus-laptop.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/asus-laptop.c b/drivers/platform/x86/asus-laptop.c
index 9a69734..15f1311 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;
 }
-- 
2.8.0