2 files changed, 35 insertions, 40 deletions

diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index aafcaa634191..f5056c7fb5be 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -460,6 +460,8 @@ event	code	Key		Notes
                                 For Lenovo ThinkPads with a new
                                 BIOS, it has to be handled either
                                 by the ACPI OSI, or by userspace.
+                                The driver does the right thing,
+                                never mess with this.
 0x1011  0x10    FN+END          Brightness down.  See brightness
                                 up for details.
 
@@ -582,46 +584,15 @@ with hotkey_report_mode.
 
 Brightness hotkey notes:
 
-These are the current sane choices for brightness key mapping in
-thinkpad-acpi:
+Don't mess with the brightness hotkeys in a Thinkpad.  If you want
+notifications for OSD, use the sysfs backlight class event support.
 
-For IBM and Lenovo models *without* ACPI backlight control (the ones on
-which thinkpad-acpi will autoload its backlight interface by default,
-and on which ACPI video does not export a backlight interface):
-
-1. Don't enable or map the brightness hotkeys in thinkpad-acpi, as
-   these older firmware versions unfortunately won't respect the hotkey
-   mask for brightness keys anyway, and always reacts to them.  This
-   usually work fine, unless X.org drivers are doing something to block
-   the BIOS.  In that case, use (3) below.  This is the default mode of
-   operation.
-
-2. Enable the hotkeys, but map them to something else that is NOT
-   KEY_BRIGHTNESS_UP/DOWN or any other keycode that would cause
-   userspace to try to change the backlight level, and use that as an
-   on-screen-display hint.
-
-3. IF AND ONLY IF X.org drivers find a way to block the firmware from
-   automatically changing the brightness, enable the hotkeys and map
-   them to KEY_BRIGHTNESS_UP and KEY_BRIGHTNESS_DOWN, and feed that to
-   something that calls xbacklight.  thinkpad-acpi will not be able to
-   change brightness in that case either, so you should disable its
-   backlight interface.
-
-For Lenovo models *with* ACPI backlight control:
-
-1. Load up ACPI video and use that.  ACPI video will report ACPI
-   events for brightness change keys.  Do not mess with thinkpad-acpi
-   defaults in this case.  thinkpad-acpi should not have anything to do
-   with backlight events in a scenario where ACPI video is loaded:
-   brightness hotkeys must be disabled, and the backlight interface is
-   to be kept disabled as well.  This is the default mode of operation.
-
-2. Do *NOT* load up ACPI video, enable the hotkeys in thinkpad-acpi,
-   and map them to KEY_BRIGHTNESS_UP and KEY_BRIGHTNESS_DOWN.  Process
-   these keys on userspace somehow (e.g. by calling xbacklight).
-   The driver will do this automatically if it detects that ACPI video
-   has been disabled.
+The driver will issue KEY_BRIGHTNESS_UP and KEY_BRIGHTNESS_DOWN events
+automatically for the cases were userspace has to do something to
+implement brightness changes.  When you override these events, you will
+either fail to handle properly the ThinkPads that require explicit
+action to change backlight brightness, or the ThinkPads that require
+that no action be taken to work properly.
 
 
 Bluetooth
@@ -1465,3 +1436,5 @@ Sysfs interface changelog:
                 and it is always able to disable hot keys.  Very old
                 thinkpads are properly supported.  hotkey_bios_mask
                 is deprecated and marked for removal.
+
+0x020600:       Marker for backlight change event support.
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index cf61d6a8ef6f..758dc0b3ed91 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -22,7 +22,7 @@
  */
 
 #define TPACPI_VERSION "0.23"
-#define TPACPI_SYSFS_VERSION 0x020500
+#define TPACPI_SYSFS_VERSION 0x020600
 
 /*
  *  Changelog:
@@ -6092,6 +6092,12 @@ static int brightness_get(struct backlight_device *bd)
         return status & TP_EC_BACKLIGHT_LVLMSK;
 }
 
+static void tpacpi_brightness_notify_change(void)
+{
+        backlight_force_update(ibm_backlight_device,
+                               BACKLIGHT_UPDATE_HOTKEY);
+}
+
 static struct backlight_ops ibm_backlight_data = {
         .get_brightness = brightness_get,
         .update_status  = brightness_update_status,
@@ -6246,6 +6252,12 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
         ibm_backlight_device->props.brightness = b & TP_EC_BACKLIGHT_LVLMSK;
         backlight_update_status(ibm_backlight_device);
 
+        vdbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_BRGHT,
+                        "brightness: registering brightness hotkeys "
+                        "as change notification\n");
+        tpacpi_hotkey_driver_mask_set(hotkey_driver_mask
+                                | TP_ACPI_HKEY_BRGHTUP_MASK
+                                | TP_ACPI_HKEY_BRGHTDWN_MASK);;
         return 0;
 }
 
@@ -6322,6 +6334,9 @@ static int brightness_write(char *buf)
          * Doing it this way makes the syscall restartable in case of EINTR
          */
         rc = brightness_set(level);
+        if (!rc && ibm_backlight_device)
+                backlight_force_update(ibm_backlight_device,
+                                        BACKLIGHT_UPDATE_SYSFS);
         return (rc == -EINTR)? -ERESTARTSYS : rc;
 }
 
@@ -7721,6 +7736,13 @@ static struct ibm_struct fan_driver_data = {
  */
 static void tpacpi_driver_event(const unsigned int hkey_event)
 {
+        if (ibm_backlight_device) {
+                switch (hkey_event) {
+                case TP_HKEY_EV_BRGHT_UP:
+                case TP_HKEY_EV_BRGHT_DOWN:
+                        tpacpi_brightness_notify_change();
+                }
+        }
 }