linux-kernel - [PATCH 10/11] platform/x86: fujitsu-laptop: account for backlight power when determining brightness

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Date:   Thu, 30 Mar 2017 12:35:08 +0200
From:   Michał Kępień <kernel@...pniu.pl>
To:     Jonathan Woithe <jwoithe@...t42.net>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 10/11] platform/x86: fujitsu-laptop: account for backlight power when determining brightness

The comment for the get_brightness backlight device callback in
include/linux/backlight.h states that it should "return the current
backlight brightness (accounting for power, fb_blank etc.)".
fujitsu-laptop violates that premise by simply returning the value to
which ACPI function GBLL evaluates to.  Make sure 0 is returned when
backlight power is turned off.

Signed-off-by: Michał Kępień <kernel@...pniu.pl>
---
 drivers/platform/x86/fujitsu-laptop.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index 78a39b143200..99befc1bc4f6 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -437,7 +437,7 @@ static int get_max_brightness(void)
 
 static int bl_get_brightness(struct backlight_device *b)
 {
-	return get_lcd_level();
+	return b->props.power == FB_BLANK_POWERDOWN ? 0 : get_lcd_level();
 }
 
 static int bl_update_status(struct backlight_device *b)
-- 
2.12.1