platform/x86: fujitsu-laptop: clean up use_alt_lcd_levels handling

The value of each module parameter can be changed on the fly via sysfs.
However, the current way of handling use_alt_lcd_levels prevents the
user from dynamically switching from a value of 0 or 1 back to
autodetection as the latter is only performed upon ACPI device
instantiation.  Fix this by moving autodetection (in a simplified form)
to set_lcd_level() and changing module parameter type to int.  Do not
announce autodetection results in a debug message as current value of
use_alt_lcd_levels can simply be read from sysfs.  Clarify module
parameter description.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>
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 4c3bba0..e79a8cf 100644 (file)
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -347,6 +347,12 @@ static int set_lcd_level(int level)
        char *method;
 
        switch (use_alt_lcd_levels) {
+       case -1:
+               if (acpi_has_method(fujitsu_bl->acpi_handle, "SBL2"))
+                       method = "SBL2";
+               else
+                       method = "SBLL";
+               break;
        case 1:
                method = "SBL2";
                break;
@@ -591,21 +597,10 @@ static int acpi_fujitsu_bl_add(struct acpi_device *device)
                        pr_err("_INI Method failed\n");
        }
 
-       if (use_alt_lcd_levels == -1) {
-               if (acpi_has_method(NULL, "\\_SB.PCI0.LPCB.FJEX.SBL2"))
-                       use_alt_lcd_levels = 1;
-               else
-                       use_alt_lcd_levels = 0;
-               vdbg_printk(FUJLAPTOP_DBG_TRACE, "auto-detected usealt as %i\n",
-                           use_alt_lcd_levels);
-       }
-
        /* do config (detect defaults) */
-       use_alt_lcd_levels = use_alt_lcd_levels == 1 ? 1 : 0;
        disable_brightness_adjust = disable_brightness_adjust == 1 ? 1 : 0;
-       vdbg_printk(FUJLAPTOP_DBG_INFO,
-                   "config: [alt interface: %d], [adjust disable: %d]\n",
-                   use_alt_lcd_levels, disable_brightness_adjust);
+       vdbg_printk(FUJLAPTOP_DBG_INFO, "config: [adjust disable: %d]\n",
+                   disable_brightness_adjust);
 
        if (get_max_brightness() <= 0)
                fujitsu_bl->max_brightness = FUJITSU_LCD_N_LEVELS;
@@ -1138,9 +1133,8 @@ static void __exit fujitsu_cleanup(void)
 module_init(fujitsu_init);
 module_exit(fujitsu_cleanup);
 
-module_param(use_alt_lcd_levels, uint, 0644);
-MODULE_PARM_DESC(use_alt_lcd_levels,
-                "Use alternative interface for lcd_levels (needed for Lifebook s6410).");
+module_param(use_alt_lcd_levels, int, 0644);
+MODULE_PARM_DESC(use_alt_lcd_levels, "Interface used for setting LCD brightness level (-1 = auto, 0 = force SBLL, 1 = force SBL2)");
 module_param(disable_brightness_adjust, uint, 0644);
 MODULE_PARM_DESC(disable_brightness_adjust, "Disable brightness adjustment .");
 #ifdef CONFIG_FUJITSU_LAPTOP_DEBUG