3 files changed, 118 insertions, 37 deletions

diff --git a/Documentation/thinkpad-acpi.txt b/Documentation/thinkpad-acpi.txt
index ec499265deca..a743bfa62b95 100644
--- a/Documentation/thinkpad-acpi.txt
+++ b/Documentation/thinkpad-acpi.txt
@@ -923,19 +923,26 @@ sysfs backlight device "thinkpad_screen"
 This feature allows software control of the LCD brightness on ThinkPad
 models which don't have a hardware brightness slider.
 
-It has some limitations: the LCD backlight cannot be actually turned on or off
-by this interface, and in many ThinkPad models, the "dim while on battery"
-functionality will be enabled by the BIOS when this interface is used, and
-cannot be controlled.
-
-The backlight control has eight levels, ranging from 0 to 7.  Some of the
-levels may not be distinct.
-
-There are two interfaces to the firmware for brightness control, EC and CMOS.
-To select which one should be used, use the brightness_mode module parameter:
-brightness_mode=1 selects EC mode, brightness_mode=2 selects CMOS mode,
-brightness_mode=3 selects both EC and CMOS.  The driver tries to autodetect
-which interface to use.
+It has some limitations: the LCD backlight cannot be actually turned on or
+off by this interface, and in many ThinkPad models, the "dim while on
+battery" functionality will be enabled by the BIOS when this interface is
+used, and cannot be controlled.
+
+On IBM (and some of the earlier Lenovo) ThinkPads, the backlight control
+has eight brightness levels, ranging from 0 to 7.  Some of the levels
+may not be distinct.  Later Lenovo models that implement the ACPI
+display backlight brightness control methods have 16 levels, ranging
+from 0 to 15.
+
+There are two interfaces to the firmware for direct brightness control,
+EC and CMOS.  To select which one should be used, use the
+brightness_mode module parameter: brightness_mode=1 selects EC mode,
+brightness_mode=2 selects CMOS mode, brightness_mode=3 selects both EC
+and CMOS.  The driver tries to autodetect which interface to use.
+
+When display backlight brightness controls are available through the
+standard ACPI interface, it is best to use it instead of this direct
+ThinkPad-specific interface.
 
 Procfs notes:
 
@@ -947,11 +954,11 @@ Procfs notes:
 
 Sysfs notes:
 
-The interface is implemented through the backlight sysfs class, which is poorly
-documented at this time.
+The interface is implemented through the backlight sysfs class, which is
+poorly documented at this time.
 
-Locate the thinkpad_screen device under /sys/class/backlight, and inside it
-there will be the following attributes:
+Locate the thinkpad_screen device under /sys/class/backlight, and inside
+it there will be the following attributes:
 
         max_brightness:
                 Reads the maximum brightness the hardware can be set to.
@@ -961,17 +968,19 @@ there will be the following attributes:
                 Reads what brightness the screen is set to at this instant.
 
         brightness:
-                Writes request the driver to change brightness to the given
-                value.  Reads will tell you what brightness the driver is trying
-                to set the display to when "power" is set to zero and the display
-                has not been dimmed by a kernel power management event.
+                Writes request the driver to change brightness to the
+                given value.  Reads will tell you what brightness the
+                driver is trying to set the display to when "power" is set
+                to zero and the display has not been dimmed by a kernel
+                power management event.
 
         power:
-                power management mode, where 0 is "display on", and 1 to 3 will
-                dim the display backlight to brightness level 0 because
-                thinkpad-acpi cannot really turn the backlight off.  Kernel
-                power management events can temporarily increase the current
-                power management level, i.e. they can dim the display.
+                power management mode, where 0 is "display on", and 1 to 3
+                will dim the display backlight to brightness level 0
+                because thinkpad-acpi cannot really turn the backlight
+                off.  Kernel power management events can temporarily
+                increase the current power management level, i.e. they can
+                dim the display.
 
 
 Volume control -- /proc/acpi/ibm/volume
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 63b1e2610c60..322ba25b4798 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -3114,6 +3114,66 @@ static struct backlight_ops ibm_backlight_data = {
 
 static struct mutex brightness_mutex;
 
+static int __init tpacpi_query_bcll_levels(acpi_handle handle)
+{
+        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+        union acpi_object *obj;
+        int rc;
+
+        if (ACPI_SUCCESS(acpi_evaluate_object(handle, NULL, NULL, &buffer))) {
+                obj = (union acpi_object *)buffer.pointer;
+                if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
+                        printk(IBM_ERR "Unknown BCLL data, "
+                               "please report this to %s\n", IBM_MAIL);
+                        rc = 0;
+                } else {
+                        rc = obj->package.count;
+                }
+        } else {
+                return 0;
+        }
+
+        kfree(buffer.pointer);
+        return rc;
+}
+
+static acpi_status __init brightness_find_bcll(acpi_handle handle, u32 lvl,
+                                        void *context, void **rv)
+{
+        char name[ACPI_PATH_SEGMENT_LENGTH];
+        struct acpi_buffer buffer = { sizeof(name), &name };
+
+        if (ACPI_SUCCESS(acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer)) &&
+            !strncmp("BCLL", name, sizeof(name) - 1)) {
+                if (tpacpi_query_bcll_levels(handle) == 16) {
+                        *rv = handle;
+                        return AE_CTRL_TERMINATE;
+                } else {
+                        return AE_OK;
+                }
+        } else {
+                return AE_OK;
+        }
+}
+
+static int __init brightness_check_levels(void)
+{
+        int status;
+        void *found_node = NULL;
+
+        if (!vid_handle) {
+                IBM_ACPIHANDLE_INIT(vid);
+        }
+        if (!vid_handle)
+                return 0;
+
+        /* Search for a BCLL package with 16 levels */
+        status = acpi_walk_namespace(ACPI_TYPE_PACKAGE, vid_handle, 3,
+                                        brightness_find_bcll, NULL, &found_node);
+
+        return (ACPI_SUCCESS(status) && found_node != NULL);
+}
+
 static int __init brightness_init(struct ibm_init_struct *iibm)
 {
         int b;
@@ -3135,10 +3195,17 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
         if (brightness_mode > 3)
                 return -EINVAL;
 
+        tp_features.bright_16levels =
+                        thinkpad_id.vendor == PCI_VENDOR_ID_LENOVO &&
+                        brightness_check_levels();
+
         b = brightness_get(NULL);
         if (b < 0)
                 return 1;
 
+        if (tp_features.bright_16levels)
+                printk(IBM_INFO "detected a 16-level brightness capable ThinkPad\n");
+
         ibm_backlight_device = backlight_device_register(
                                         TPACPI_BACKLIGHT_DEV_NAME, NULL, NULL,
                                         &ibm_backlight_data);
@@ -3148,7 +3215,8 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
         }
         vdbg_printk(TPACPI_DBG_INIT, "brightness is supported\n");
 
-        ibm_backlight_device->props.max_brightness = 7;
+        ibm_backlight_device->props.max_brightness =
+                                (tp_features.bright_16levels)? 15 : 7;
         ibm_backlight_device->props.brightness = b;
         backlight_update_status(ibm_backlight_device);
 
@@ -3184,13 +3252,14 @@ static int brightness_get(struct backlight_device *bd)
         if (brightness_mode & 1) {
                 if (!acpi_ec_read(brightness_offset, &lec))
                         return -EIO;
-                lec &= 7;
+                lec &= (tp_features.bright_16levels)? 0x0f : 0x07;
                 level = lec;
         };
         if (brightness_mode & 2) {
                 lcmos = (nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
                          & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
                         >> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
+                lcmos &= (tp_features.bright_16levels)? 0x0f : 0x07;
                 level = lcmos;
         }
 
@@ -3211,7 +3280,7 @@ static int brightness_set(int value)
         int cmos_cmd, inc, i, res;
         int current_value;
 
-        if (value > 7)
+        if (value > ((tp_features.bright_16levels)? 15 : 7))
                 return -EINVAL;
 
         res = mutex_lock_interruptible(&brightness_mutex);
@@ -3227,7 +3296,7 @@ static int brightness_set(int value)
         cmos_cmd = value > current_value ?
                         TP_CMOS_BRIGHTNESS_UP :
                         TP_CMOS_BRIGHTNESS_DOWN;
-        inc = value > current_value ? 1 : -1;
+        inc = (value > current_value)? 1 : -1;
 
         res = 0;
         for (i = current_value; i != value; i += inc) {
@@ -3256,10 +3325,11 @@ static int brightness_read(char *p)
         if ((level = brightness_get(NULL)) < 0) {
                 len += sprintf(p + len, "level:\t\tunreadable\n");
         } else {
-                len += sprintf(p + len, "level:\t\t%d\n", level & 0x7);
+                len += sprintf(p + len, "level:\t\t%d\n", level);
                 len += sprintf(p + len, "commands:\tup, down\n");
                 len += sprintf(p + len, "commands:\tlevel <level>"
-                               " (<level> is 0-7)\n");
+                               " (<level> is 0-%d)\n",
+                               (tp_features.bright_16levels) ? 15 : 7);
         }
 
         return len;
@@ -3270,18 +3340,19 @@ static int brightness_write(char *buf)
         int level;
         int new_level;
         char *cmd;
+        int max_level = (tp_features.bright_16levels) ? 15 : 7;
 
         while ((cmd = next_cmd(&buf))) {
                 if ((level = brightness_get(NULL)) < 0)
                         return level;
-                level &= 7;
 
                 if (strlencmp(cmd, "up") == 0) {
-                        new_level = level == 7 ? 7 : level + 1;
+                        new_level = level == (max_level)?
+                                                max_level : level + 1;
                 } else if (strlencmp(cmd, "down") == 0) {
-                        new_level = level == 0 ? 0 : level - 1;
+                        new_level = level == 0? 0 : level - 1;
                 } else if (sscanf(cmd, "level %d", &new_level) == 1 &&
-                           new_level >= 0 && new_level <= 7) {
+                           new_level >= 0 && new_level <= max_level) {
                         /* new_level set */
                 } else
                         return -EINVAL;
diff --git a/drivers/misc/thinkpad_acpi.h b/drivers/misc/thinkpad_acpi.h
index 3abcc8120634..8ca19c333727 100644
--- a/drivers/misc/thinkpad_acpi.h
+++ b/drivers/misc/thinkpad_acpi.h
@@ -84,7 +84,7 @@
 
 /* ThinkPad CMOS NVRAM constants */
 #define TP_NVRAM_ADDR_BRIGHTNESS       0x5e
-#define TP_NVRAM_MASK_LEVEL_BRIGHTNESS 0x07
+#define TP_NVRAM_MASK_LEVEL_BRIGHTNESS 0x0f
 #define TP_NVRAM_POS_LEVEL_BRIGHTNESS 0
 
 #define onoff(status,bit) ((status) & (1 << (bit)) ? "on" : "off")
@@ -246,6 +246,7 @@ static struct {
         u32 hotkey_wlsw:1;
         u32 light:1;
         u32 light_status:1;
+        u32 bright_16levels:1;
         u32 wan:1;
         u32 fan_ctrl_status_undef:1;
         u32 input_device_registered:1;