2 files changed, 183 insertions, 105 deletions

diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index 76cb428435da..a77da28a6f8e 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -571,6 +571,47 @@ netlink interface and the input layer interface, and don't bother at all
 with hotkey_report_mode.
 
 
+Brightness hotkey notes:
+
+These are the current sane choices for brightness key mapping in
+thinkpad-acpi:
+
+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).
+
 Bluetooth
 ---------
 
@@ -1090,6 +1131,15 @@ it there will be the following attributes:
                 dim the display.
 
 
+WARNING:
+
+    Whatever you do, do NOT ever call thinkpad-acpi backlight-level change
+    interface and the ACPI-based backlight level change interface
+    (available on newer BIOSes, and driven by the Linux ACPI video driver)
+    at the same time.  The two will interact in bad ways, do funny things,
+    and maybe reduce the life of the backlight lamps by needlessly kicking
+    its level up and down at every change.
+
 Volume control -- /proc/acpi/ibm/volume
 ---------------------------------------
 
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 6cb781262f94..2c85a2e10a25 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -225,6 +225,7 @@ static struct {
         u32 light:1;
         u32 light_status:1;
         u32 bright_16levels:1;
+        u32 bright_acpimode:1;
         u32 wan:1;
         u32 fan_ctrl_status_undef:1;
         u32 input_device_registered:1;
@@ -807,6 +808,80 @@ static int parse_strtoul(const char *buf,
         return 0;
 }
 
+static int __init tpacpi_query_bcl_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(TPACPI_ERR "Unknown _BCL data, "
+                               "please report this to %s\n", TPACPI_MAIL);
+                        rc = 0;
+                } else {
+                        rc = obj->package.count;
+                }
+        } else {
+                return 0;
+        }
+
+        kfree(buffer.pointer);
+        return rc;
+}
+
+static acpi_status __init tpacpi_acpi_walk_find_bcl(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("_BCL", name, sizeof(name) - 1)) {
+                BUG_ON(!rv || !*rv);
+                **(int **)rv = tpacpi_query_bcl_levels(handle);
+                return AE_CTRL_TERMINATE;
+        } else {
+                return AE_OK;
+        }
+}
+
+/*
+ * Returns 0 (no ACPI _BCL or _BCL invalid), or size of brightness map
+ */
+static int __init tpacpi_check_std_acpi_brightness_support(void)
+{
+        int status;
+        int bcl_levels = 0;
+        void *bcl_ptr = &bcl_levels;
+
+        if (!vid_handle) {
+                TPACPI_ACPIHANDLE_INIT(vid);
+        }
+        if (!vid_handle)
+                return 0;
+
+        /*
+         * Search for a _BCL method, and execute it.  This is safe on all
+         * ThinkPads, and as a side-effect, _BCL will place a Lenovo Vista
+         * BIOS in ACPI backlight control mode.  We do NOT have to care
+         * about calling the _BCL method in an enabled video device, any
+         * will do for our purposes.
+         */
+
+        status = acpi_walk_namespace(ACPI_TYPE_METHOD, vid_handle, 3,
+                                     tpacpi_acpi_walk_find_bcl, NULL,
+                                     &bcl_ptr);
+
+        if (ACPI_SUCCESS(status) && bcl_levels > 2) {
+                tp_features.bright_acpimode = 1;
+                return (bcl_levels - 2);
+        }
+
+        return 0;
+}
+
 /*************************************************************************
  * thinkpad-acpi driver attributes
  */
@@ -1887,6 +1962,9 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
                 KEY_UNKNOWN,    /* 0x0D: FN+INSERT */
                 KEY_UNKNOWN,    /* 0x0E: FN+DELETE */
 
+                /* These either have to go through ACPI video, or
+                 * act like in the IBM ThinkPads, so don't ever
+                 * enable them by default */
                 KEY_RESERVED,   /* 0x0F: FN+HOME (brightness up) */
                 KEY_RESERVED,   /* 0x10: FN+END (brightness down) */
 
@@ -2091,6 +2169,32 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
                         set_bit(SW_TABLET_MODE, tpacpi_inputdev->swbit);
                 }
 
+                /* Do not issue duplicate brightness change events to
+                 * userspace */
+                if (!tp_features.bright_acpimode)
+                        /* update bright_acpimode... */
+                        tpacpi_check_std_acpi_brightness_support();
+
+                if (tp_features.bright_acpimode) {
+                        printk(TPACPI_INFO
+                               "This ThinkPad has standard ACPI backlight "
+                               "brightness control, supported by the ACPI "
+                               "video driver\n");
+                        printk(TPACPI_NOTICE
+                               "Disabling thinkpad-acpi brightness events "
+                               "by default...\n");
+
+                        /* The hotkey_reserved_mask change below is not
+                         * necessary while the keys are at KEY_RESERVED in the
+                         * default map, but better safe than sorry, leave it
+                         * here as a marker of what we have to do, especially
+                         * when we finally become able to set this at runtime
+                         * on response to X.org requests */
+                        hotkey_reserved_mask |=
+                                (1 << TP_ACPI_HOTKEYSCAN_FNHOME)
+                                | (1 << TP_ACPI_HOTKEYSCAN_FNEND);
+                }
+
                 dbg_printk(TPACPI_DBG_INIT,
                                 "enabling hot key handling\n");
                 res = hotkey_status_set(1);
@@ -4273,100 +4377,6 @@ static struct backlight_ops ibm_backlight_data = {
 
 /* --------------------------------------------------------------------- */
 
-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(TPACPI_ERR "Unknown BCLL data, "
-                               "please report this to %s\n", TPACPI_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) {
-                TPACPI_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 acpi_status __init brightness_find_bcl(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("_BCL", name, sizeof(name) - 1)) {
-                *rv = handle;
-                return AE_CTRL_TERMINATE;
-        } else {
-                return AE_OK;
-        }
-}
-
-static int __init brightness_check_std_acpi_support(void)
-{
-        int status;
-        void *found_node = NULL;
-
-        if (!vid_handle) {
-                TPACPI_ACPIHANDLE_INIT(vid);
-        }
-        if (!vid_handle)
-                return 0;
-
-        /* Search for a _BCL method, but don't execute it */
-        status = acpi_walk_namespace(ACPI_TYPE_METHOD, vid_handle, 3,
-                                     brightness_find_bcl, NULL, &found_node);
-
-        return (ACPI_SUCCESS(status) && found_node != NULL);
-}
-
 static int __init brightness_init(struct ibm_init_struct *iibm)
 {
         int b;
@@ -4375,13 +4385,19 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
 
         mutex_init(&brightness_mutex);
 
-        if (!brightness_enable) {
-                dbg_printk(TPACPI_DBG_INIT,
-                           "brightness support disabled by "
-                           "module parameter\n");
-                return 1;
-        } else if (brightness_enable > 1) {
-                if (brightness_check_std_acpi_support()) {
+        /*
+         * We always attempt to detect acpi support, so as to switch
+         * Lenovo Vista BIOS to ACPI brightness mode even if we are not
+         * going to publish a backlight interface
+         */
+        b = tpacpi_check_std_acpi_brightness_support();
+        if (b > 0) {
+                if (thinkpad_id.vendor == PCI_VENDOR_ID_LENOVO) {
+                        printk(TPACPI_NOTICE
+                               "Lenovo BIOS switched to ACPI backlight "
+                               "control mode\n");
+                }
+                if (brightness_enable > 1) {
                         printk(TPACPI_NOTICE
                                "standard ACPI backlight interface "
                                "available, not loading native one...\n");
@@ -4389,6 +4405,22 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
                 }
         }
 
+        if (!brightness_enable) {
+                dbg_printk(TPACPI_DBG_INIT,
+                           "brightness support disabled by "
+                           "module parameter\n");
+                return 1;
+        }
+
+        if (b > 16) {
+                printk(TPACPI_ERR
+                       "Unsupported brightness interface, "
+                       "please contact %s\n", TPACPI_MAIL);
+                return 1;
+        }
+        if (b == 16)
+                tp_features.bright_16levels = 1;
+
         if (!brightness_mode) {
                 if (thinkpad_id.vendor == PCI_VENDOR_ID_LENOVO)
                         brightness_mode = 2;
@@ -4402,10 +4434,6 @@ 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;