linux-kernel - [PATCH v3 2/2] backlight: pwm_bl: Check the pwm state for initial backlight power state

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:   Tue, 1 Nov 2016 14:59:33 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <thierry.reding@...il.com>, <lee.jones@...aro.org>
CC:     <tomi.valkeinen@...com>, <linux-pwm@...r.kernel.org>,
        <linux-fbdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <p.zabel@...gutronix.de>
Subject: [PATCH v3 2/2] backlight: pwm_bl: Check the pwm state for initial backlight power state

If the pwm is not enabled the backlight initially should not be enabled
either if we have booted with DT and there is a phandle pointing to the
backlight node.

The patch extends the checks to decide if we should keep the backlight off
initially.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
 drivers/video/backlight/pwm_bl.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 4b07da278b4f..f680f7b033b2 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -215,6 +215,10 @@ static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb)
 	if (!regulator_is_enabled(pb->power_supply))
 		return FB_BLANK_POWERDOWN;
 
+	/* The pwm is disabled, keep it like this */
+	if (!pwm_is_enabled(pb->pwm))
+		return FB_BLANK_POWERDOWN;
+
 	return FB_BLANK_UNBLANK;
 }
 
-- 
2.10.2