toshiba_acpi: Fix regression caused by backlight extra check code

Bug 86521 uncovered that some TOS6208 devices also return
non zero values on a write call to the backlight method,
thus getting caught and bailed out by the extra check code.

This patch changes the set_lcd_brightness function to its
"original" state by just adapting it to the new function
format.
Signed-off-by: Azael Avalos <coproscefalo@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

drivers/platform/x86/toshiba_acpi.c

@@ -928,9 +928,7 @@ static int lcd_proc_open(struct inode *inode, struct file *file)
 
 static int set_lcd_brightness(struct toshiba_acpi_dev *dev, int value)
 {
-	u32 in[TCI_WORDS] = { HCI_SET, HCI_LCD_BRIGHTNESS, 0, 0, 0, 0 };
-	u32 out[TCI_WORDS];
-	acpi_status status;
+	u32 hci_result;
 
 	if (dev->tr_backlight_supported) {
 		bool enable = !value;
@@ -941,20 +939,9 @@ static int set_lcd_brightness(struct toshiba_acpi_dev *dev, int value)
 			value--;
 	}
 
-	in[2] = value << HCI_LCD_BRIGHTNESS_SHIFT;
-	status = tci_raw(dev, in, out);
-	if (ACPI_FAILURE(status) || out[0] == TOS_FAILURE) {
-		pr_err("ACPI call to set brightness failed");
-		return -EIO;
-	}
-	/* Extra check for "incomplete" backlight method, where the AML code
-	 * doesn't check for HCI_SET or HCI_GET and returns TOS_SUCCESS,
-	 * the actual brightness, and in some cases the max brightness.
-	 */
-	if (out[2] > 0  || out[3] == 0xE000)
-		return -ENODEV;
-
-	return out[0] == TOS_SUCCESS ? 0 : -EIO;
+	value = value << HCI_LCD_BRIGHTNESS_SHIFT;
+	hci_result = hci_write1(dev, HCI_LCD_BRIGHTNESS, value);
+	return hci_result == TOS_SUCCESS ? 0 : -EIO;
 }
 
 static int set_lcd_status(struct backlight_device *bd)