linux-kernel - [PATCH 2/2] backlight: lp855x: Catch errors when changing brightness

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]

Date:   Fri, 14 Jul 2023 14:14:40 +0200
From:   Artur Weber <aweber.kernel@...il.com>
To:     Lee Jones <lee@...nel.org>
Cc:     Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Helge Deller <deller@....de>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Artur Weber <aweber.kernel@...il.com>,
        dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht
Subject: [PATCH 2/2] backlight: lp855x: Catch errors when changing brightness

The lp855x_bl_update_status function's return type is int, but
it always returns 0, without checking for the results of the
write_byte/pwm_ctrl functions called within.

Make this function return the return values of the functions it
calls, and modify the lp855x_pwm_ctrl function to return errors.

Signed-off-by: Artur Weber <aweber.kernel@...il.com>
---
 drivers/video/backlight/lp855x_bl.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index 349ec324bc1e..61a7f45bfad8 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -217,7 +217,7 @@ static int lp855x_configure(struct lp855x *lp)
 	return ret;
 }
 
-static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
+static int lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 {
 	struct pwm_state state;
 
@@ -234,23 +234,26 @@ static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 	state.duty_cycle = div_u64(br * state.period, max_br);
 	state.enabled = state.duty_cycle;
 
-	pwm_apply_state(lp->pwm, &state);
+	return pwm_apply_state(lp->pwm, &state);
 }
 
 static int lp855x_bl_update_status(struct backlight_device *bl)
 {
 	struct lp855x *lp = bl_get_data(bl);
 	int brightness = bl->props.brightness;
+	int ret;
 
 	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 		brightness = 0;
 
 	if (lp->mode == PWM_BASED)
-		lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
+		ret = lp855x_pwm_ctrl(lp, brightness,
+				      bl->props.max_brightness);
 	else if (lp->mode == REGISTER_BASED)
-		lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
+		ret = lp855x_write_byte(lp, lp->cfg->reg_brightness,
+					(u8)brightness);
 
-	return 0;
+	return ret;
 }
 
 static const struct backlight_ops lp855x_bl_ops = {
-- 
2.41.0