sony-laptop: don't change keyboard backlight settings

Do not touch keyboard backlight unless explicitly passed a module
parameter.  In this way we won't make wrong assumptions about what are
good default values since they actually are different from model to
model.

The only side effect is that we won't know what is the current value
until set via the sysfs attributes.
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/platform/x86/sony-laptop.c

@@ -127,18 +127,17 @@ MODULE_PARM_DESC(minor,
 		 "default is -1 (automatic)");
 #endif
 
-static int kbd_backlight = 1;
+static int kbd_backlight = -1;
 module_param(kbd_backlight, int, 0444);
 MODULE_PARM_DESC(kbd_backlight,
 		 "set this to 0 to disable keyboard backlight, "
-		 "1 to enable it (default: 0)");
+		 "1 to enable it (default: no change from current value)");
 
-static int kbd_backlight_timeout;	/* = 0 */
+static int kbd_backlight_timeout = -1;
 module_param(kbd_backlight_timeout, int, 0444);
 MODULE_PARM_DESC(kbd_backlight_timeout,
-		 "set this to 0 to set the default 10 seconds timeout, "
-		 "1 for 30 seconds, 2 for 60 seconds and 3 to disable timeout "
-		 "(default: 0)");
+		 "meaningful values vary from 0 to 3 and their meaning depends "
+		 "on the model (default: no change from current value)");
 
 #ifdef CONFIG_PM_SLEEP
 static void sony_nc_kbd_backlight_resume(void);
@@ -1844,6 +1843,8 @@ static int sony_nc_kbd_backlight_setup(struct platform_device *pd,
 	if (!kbdbl_ctl)
 		return -ENOMEM;
 
+	kbdbl_ctl->mode = kbd_backlight;
+	kbdbl_ctl->timeout = kbd_backlight_timeout;
 	kbdbl_ctl->handle = handle;
 	if (handle == 0x0137)
 		kbdbl_ctl->base = 0x0C00;
@@ -1870,8 +1871,8 @@ static int sony_nc_kbd_backlight_setup(struct platform_device *pd,
 	if (ret)
 		goto outmode;
 
-	__sony_nc_kbd_backlight_mode_set(kbd_backlight);
-	__sony_nc_kbd_backlight_timeout_set(kbd_backlight_timeout);
+	__sony_nc_kbd_backlight_mode_set(kbdbl_ctl->mode);
+	__sony_nc_kbd_backlight_timeout_set(kbdbl_ctl->timeout);
 
 	return 0;
 
@@ -1886,17 +1887,8 @@ static int sony_nc_kbd_backlight_setup(struct platform_device *pd,
 static void sony_nc_kbd_backlight_cleanup(struct platform_device *pd)
 {
 	if (kbdbl_ctl) {
-		int result;
-
 		device_remove_file(&pd->dev, &kbdbl_ctl->mode_attr);
 		device_remove_file(&pd->dev, &kbdbl_ctl->timeout_attr);
-
-		/* restore the default hw behaviour */
-		sony_call_snc_handle(kbdbl_ctl->handle,
-				kbdbl_ctl->base | 0x10000, &result);
-		sony_call_snc_handle(kbdbl_ctl->handle,
-				kbdbl_ctl->base + 0x200, &result);
-
 		kfree(kbdbl_ctl);
 		kbdbl_ctl = NULL;
 	}