FAILED: patch "[PATCH] platform/x86: fujitsu-laptop: Don't oops when FUJ02E3 is not" failed to apply to 4.14-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From cd6bf7741cf992306748db11e1888c741d16dd0f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Mon, 18 Sep 2017 23:00:59 +0300
Subject: [PATCH] platform/x86: fujitsu-laptop: Don't oops when FUJ02E3 is not
 presnt
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

My Fujitsu-Siemens Lifebook S6120 doesn't have the FUJ02E3 device,
but it does have FUJ02B1. That means we do register the backlight
device (and it even seems to work), but the code will oops as soon
as we try to set the backlight brightness because it's trying to
call call_fext_func() with a NULL device. Let's just skip those
function calls when the FUJ02E3 device is not present.

Cc: Jonathan Woithe <jwoithe@just42.net>
Cc: Andy Shevchenko <andy@infradead.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org> # 4.13.x
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index 85de30f93a9c..56a8195096a2 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -254,10 +254,12 @@ static int bl_update_status(struct backlight_device *b)
 {
 	struct acpi_device *device = bl_get_data(b);
 
-	if (b->props.power == FB_BLANK_POWERDOWN)
-		call_fext_func(fext, FUNC_BACKLIGHT, 0x1, 0x4, 0x3);
-	else
-		call_fext_func(fext, FUNC_BACKLIGHT, 0x1, 0x4, 0x0);
+	if (fext) {
+		if (b->props.power == FB_BLANK_POWERDOWN)
+			call_fext_func(fext, FUNC_BACKLIGHT, 0x1, 0x4, 0x3);
+		else
+			call_fext_func(fext, FUNC_BACKLIGHT, 0x1, 0x4, 0x0);
+	}
 
 	return set_lcd_level(device, b->props.brightness);
 }