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:
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.
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
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;
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);
}
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);
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;
}
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);
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) {
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;
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;
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff