platform/x86: sony-laptop: Don't turn off 0x153 keyboard backlight du…

…ring probe

commit ad75bd8 upstream.

The 0x153 version of the kbd backlight control SNC handle has no separate
address to probe if the backlight is there.

This turns the probe call into a set keyboard backlight call with a value
of 0 turning off the keyboard backlight.

Skip probing when there is no separate probe address to avoid this.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1583752
Fixes: 800f201 ("Keyboard backlight control for some Vaio Fit models")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mattia Dongili <malattia@linux.it>
Link: https://lore.kernel.org/r/20221213122943.11123-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/platform/x86/sony-laptop.c

@@ -1888,14 +1888,21 @@ static int sony_nc_kbd_backlight_setup(struct platform_device *pd,
 		break;
 	}
 
-	ret = sony_call_snc_handle(handle, probe_base, &result);
-	if (ret)
-		return ret;
+	/*
+	 * Only probe if there is a separate probe_base, otherwise the probe call
+	 * is equivalent to __sony_nc_kbd_backlight_mode_set(0), resulting in
+	 * the keyboard backlight being turned off.
+	 */
+	if (probe_base) {
+		ret = sony_call_snc_handle(handle, probe_base, &result);
+		if (ret)
+			return ret;
 
-	if ((handle == 0x0137 && !(result & 0x02)) ||
-			!(result & 0x01)) {
-		dprintk("no backlight keyboard found\n");
-		return 0;
+		if ((handle == 0x0137 && !(result & 0x02)) ||
+				!(result & 0x01)) {
+			dprintk("no backlight keyboard found\n");
+			return 0;
+		}
 	}
 
 	kbdbl_ctl = kzalloc(sizeof(*kbdbl_ctl), GFP_KERNEL);