linux-kernel - [PATCHv2] pwm_backlight: pass correct brightness to callback

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1341812161-13328-1-git-send-email-acourbot@nvidia.com>
Date:	Mon, 9 Jul 2012 14:36:01 +0900
From:	Alexandre Courbot <acourbot@...dia.com>
To:	Thierry Reding <thierry.reding@...onic-design.de>
CC:	<linux-kernel@...r.kernel.org>, <linux-fbdev@...r.kernel.org>,
	Alexandre Courbot <acourbot@...dia.com>
Subject: [PATCHv2] 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@...dia.com>
---
 drivers/video/backlight/pwm_bl.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 057389d..6d1d3ea 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -39,6 +39,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
 {
 	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
 	int brightness = bl->props.brightness;
+	int pwm_brightness;
 	int max = bl->props.max_brightness;
 
 	if (bl->props.power != FB_BLANK_UNBLANK)
@@ -55,13 +56,15 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
 		pwm_disable(pb->pwm);
 	} else {
 		if (pb->levels) {
-			brightness = pb->levels[brightness];
+			pwm_brightness = pb->levels[brightness];
 			max = pb->levels[max];
+		} else {
+			pwm_brightness = brightness;
 		}
 
-		brightness = pb->lth_brightness +
-			(brightness * (pb->period - pb->lth_brightness) / max);
-		pwm_config(pb->pwm, brightness, pb->period);
+		pwm_brightness = pb->lth_brightness +
+		     (pwm_brightness * (pb->period - pb->lth_brightness) / max);
+		pwm_config(pb->pwm, pwm_brightness, pb->period);
 		pwm_enable(pb->pwm);
 	}
 
-- 
1.7.11.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/