From: Alexandre Courbot <acourbot@nvidia.com>
Date: Mon, 9 Jul 2012 06:04:23 +0000 (+0900)
Subject: pwm_backlight: pass correct brightness to callback
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=9fb978b12f9cc2b4df428764273d96877d0a262d;p=deliverable%2Flinux.git

pwm_backlight: pass correct brightness to callback

pwm_backlight_update_status calls the notify() and notify_after()
callbacks before and after applying the new PWM settings. However, if
brightness levels are used, the brightness value will be changed from
the index into the levels array to the PWM duty cycle length before
being passed to notify_after(), which results in inconsistent behavior.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
---

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 057389d69a51..995f0164c9b0 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -54,14 +54,18 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
 		pwm_config(pb->pwm, 0, pb->period);
 		pwm_disable(pb->pwm);
 	} else {
+		int duty_cycle;
+
 		if (pb->levels) {
-			brightness = pb->levels[brightness];
+			duty_cycle = pb->levels[brightness];
 			max = pb->levels[max];
+		} else {
+			duty_cycle = brightness;
 		}
 
-		brightness = pb->lth_brightness +
-			(brightness * (pb->period - pb->lth_brightness) / max);
-		pwm_config(pb->pwm, brightness, pb->period);
+		duty_cycle = pb->lth_brightness +
+		     (duty_cycle * (pb->period - pb->lth_brightness) / max);
+		pwm_config(pb->pwm, duty_cycle, pb->period);
 		pwm_enable(pb->pwm);
 	}