cs5535: add a generic clock event MFGPT driver
[safe/jmp/linux-2.6] / drivers / acpi / video.c
index 100c8ee..05dff63 100644 (file)
 #include <linux/pci.h>
 #include <linux/pci_ids.h>
 #include <asm/uaccess.h>
-
+#include <linux/dmi.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 
+#define PREFIX "ACPI: "
+
 #define ACPI_VIDEO_CLASS               "video"
 #define ACPI_VIDEO_BUS_NAME            "Video Bus"
 #define ACPI_VIDEO_DEVICE_NAME         "Video Device"
@@ -76,9 +78,11 @@ MODULE_LICENSE("GPL");
 static int brightness_switch_enabled = 1;
 module_param(brightness_switch_enabled, bool, 0644);
 
+static int register_count = 0;
 static int acpi_video_bus_add(struct acpi_device *device);
 static int acpi_video_bus_remove(struct acpi_device *device, int type);
 static int acpi_video_resume(struct acpi_device *device);
+static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
 
 static const struct acpi_device_id video_device_ids[] = {
        {ACPI_VIDEO_HID, 0},
@@ -94,6 +98,7 @@ static struct acpi_driver acpi_video_bus = {
                .add = acpi_video_bus_add,
                .remove = acpi_video_bus_remove,
                .resume = acpi_video_resume,
+               .notify = acpi_video_bus_notify,
                },
 };
 
@@ -195,13 +200,13 @@ struct acpi_video_device {
        struct acpi_device *dev;
        struct acpi_video_device_brightness *brightness;
        struct backlight_device *backlight;
-       struct thermal_cooling_device *cdev;
+       struct thermal_cooling_device *cooling_dev;
        struct output_device *output_dev;
 };
 
 /* bus */
 static int acpi_video_bus_info_open_fs(struct inode *inode, struct file *file);
-static struct file_operations acpi_video_bus_info_fops = {
+static const struct file_operations acpi_video_bus_info_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_bus_info_open_fs,
        .read = seq_read,
@@ -210,7 +215,7 @@ static struct file_operations acpi_video_bus_info_fops = {
 };
 
 static int acpi_video_bus_ROM_open_fs(struct inode *inode, struct file *file);
-static struct file_operations acpi_video_bus_ROM_fops = {
+static const struct file_operations acpi_video_bus_ROM_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_bus_ROM_open_fs,
        .read = seq_read,
@@ -220,7 +225,7 @@ static struct file_operations acpi_video_bus_ROM_fops = {
 
 static int acpi_video_bus_POST_info_open_fs(struct inode *inode,
                                            struct file *file);
-static struct file_operations acpi_video_bus_POST_info_fops = {
+static const struct file_operations acpi_video_bus_POST_info_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_bus_POST_info_open_fs,
        .read = seq_read,
@@ -229,19 +234,25 @@ static struct file_operations acpi_video_bus_POST_info_fops = {
 };
 
 static int acpi_video_bus_POST_open_fs(struct inode *inode, struct file *file);
-static struct file_operations acpi_video_bus_POST_fops = {
+static ssize_t acpi_video_bus_write_POST(struct file *file,
+       const char __user *buffer, size_t count, loff_t *data);
+static const struct file_operations acpi_video_bus_POST_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_bus_POST_open_fs,
        .read = seq_read,
+       .write = acpi_video_bus_write_POST,
        .llseek = seq_lseek,
        .release = single_release,
 };
 
 static int acpi_video_bus_DOS_open_fs(struct inode *inode, struct file *file);
-static struct file_operations acpi_video_bus_DOS_fops = {
+static ssize_t acpi_video_bus_write_DOS(struct file *file,
+       const char __user *buffer, size_t count, loff_t *data);
+static const struct file_operations acpi_video_bus_DOS_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_bus_DOS_open_fs,
        .read = seq_read,
+       .write = acpi_video_bus_write_DOS,
        .llseek = seq_lseek,
        .release = single_release,
 };
@@ -249,7 +260,7 @@ static struct file_operations acpi_video_bus_DOS_fops = {
 /* device */
 static int acpi_video_device_info_open_fs(struct inode *inode,
                                          struct file *file);
-static struct file_operations acpi_video_device_info_fops = {
+static const struct file_operations acpi_video_device_info_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_device_info_open_fs,
        .read = seq_read,
@@ -259,27 +270,33 @@ static struct file_operations acpi_video_device_info_fops = {
 
 static int acpi_video_device_state_open_fs(struct inode *inode,
                                           struct file *file);
-static struct file_operations acpi_video_device_state_fops = {
+static ssize_t acpi_video_device_write_state(struct file *file,
+       const char __user *buffer, size_t count, loff_t *data);
+static const struct file_operations acpi_video_device_state_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_device_state_open_fs,
        .read = seq_read,
+       .write = acpi_video_device_write_state,
        .llseek = seq_lseek,
        .release = single_release,
 };
 
 static int acpi_video_device_brightness_open_fs(struct inode *inode,
                                                struct file *file);
-static struct file_operations acpi_video_device_brightness_fops = {
+static ssize_t acpi_video_device_write_brightness(struct file *file,
+       const char __user *buffer, size_t count, loff_t *data);
+static const struct file_operations acpi_video_device_brightness_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_device_brightness_open_fs,
        .read = seq_read,
+       .write = acpi_video_device_write_brightness,
        .llseek = seq_lseek,
        .release = single_release,
 };
 
 static int acpi_video_device_EDID_open_fs(struct inode *inode,
                                          struct file *file);
-static struct file_operations acpi_video_device_EDID_fops = {
+static const struct file_operations acpi_video_device_EDID_fops = {
        .owner = THIS_MODULE,
        .open = acpi_video_device_EDID_open_fs,
        .read = seq_read,
@@ -287,7 +304,7 @@ static struct file_operations acpi_video_device_EDID_fops = {
        .release = single_release,
 };
 
-static char device_decode[][30] = {
+static const char device_decode[][30] = {
        "motherboard VGA device",
        "PCI VGA device",
        "AGP VGA device",
@@ -372,20 +389,20 @@ static struct output_properties acpi_output_properties = {
 
 
 /* thermal cooling device callbacks */
-static int video_get_max_state(struct thermal_cooling_device *cdev, unsigned
+static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
                               long *state)
 {
-       struct acpi_device *device = cdev->devdata;
+       struct acpi_device *device = cooling_dev->devdata;
        struct acpi_video_device *video = acpi_driver_data(device);
 
        *state = video->brightness->count - 3;
        return 0;
 }
 
-static int video_get_cur_state(struct thermal_cooling_device *cdev, unsigned
+static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
                               long *state)
 {
-       struct acpi_device *device = cdev->devdata;
+       struct acpi_device *device = cooling_dev->devdata;
        struct acpi_video_device *video = acpi_driver_data(device);
        unsigned long long level;
        int offset;
@@ -402,9 +419,9 @@ static int video_get_cur_state(struct thermal_cooling_device *cdev, unsigned
 }
 
 static int
-video_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
+video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 {
-       struct acpi_device *device = cdev->devdata;
+       struct acpi_device *device = cooling_dev->devdata;
        struct acpi_video_device *video = acpi_driver_data(device);
        int level;
 
@@ -524,11 +541,71 @@ acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
        return -EINVAL;
 }
 
+/*
+ * For some buggy _BQC methods, we need to add a constant value to
+ * the _BQC return value to get the actual current brightness level
+ */
+
+static int bqc_offset_aml_bug_workaround;
+static int __init video_set_bqc_offset(const struct dmi_system_id *d)
+{
+       bqc_offset_aml_bug_workaround = 9;
+       return 0;
+}
+
+static struct dmi_system_id video_dmi_table[] __initdata = {
+       /*
+        * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
+        */
+       {
+        .callback = video_set_bqc_offset,
+        .ident = "Acer Aspire 5720",
+        .matches = {
+               DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
+               },
+       },
+       {
+        .callback = video_set_bqc_offset,
+        .ident = "Acer Aspire 5710Z",
+        .matches = {
+               DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
+               },
+       },
+       {
+        .callback = video_set_bqc_offset,
+        .ident = "eMachines E510",
+        .matches = {
+               DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
+               },
+       },
+       {
+        .callback = video_set_bqc_offset,
+        .ident = "Acer Aspire 5315",
+        .matches = {
+               DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
+               },
+       },
+       {
+        .callback = video_set_bqc_offset,
+        .ident = "Acer Aspire 7720",
+        .matches = {
+               DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
+               },
+       },
+       {}
+};
+
 static int
 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
                                        unsigned long long *level)
 {
        acpi_status status = AE_OK;
+       int i;
 
        if (device->cap._BQC || device->cap._BCQ) {
                char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
@@ -543,8 +620,16 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
                                *level = device->brightness->levels[*level + 2];
 
                        }
-                       device->brightness->curr = *level;
-                       return 0;
+                       *level += bqc_offset_aml_bug_workaround;
+                       for (i = 2; i < device->brightness->count; i++)
+                               if (device->brightness->levels[i] == *level) {
+                                       device->brightness->curr = *level;
+                                       return 0;
+                       }
+                       /* BQC returned an invalid level. Stop using it.  */
+                       ACPI_WARNING((AE_INFO, "%s returned an invalid level",
+                                               buf));
+                       device->cap._BQC = device->cap._BCQ = 0;
                } else {
                        /* Fixme:
                         * should we return an error or ignore this failure?
@@ -756,10 +841,12 @@ acpi_video_init_brightness(struct acpi_video_device *device)
         * In this case, the first two elements in _BCL packages
         * are also supported brightness levels that OS should take care of.
         */
-       for (i = 2; i < count; i++)
-               if (br->levels[i] == br->levels[0] ||
-                   br->levels[i] == br->levels[1])
+       for (i = 2; i < count; i++) {
+               if (br->levels[i] == br->levels[0])
+                       level_ac_battery++;
+               if (br->levels[i] == br->levels[1])
                        level_ac_battery++;
+       }
 
        if (level_ac_battery < 2) {
                level_ac_battery = 2 - level_ac_battery;
@@ -793,12 +880,19 @@ acpi_video_init_brightness(struct acpi_video_device *device)
        br->flags._BCM_use_index = br->flags._BCL_use_index;
 
        /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
-       br->curr = max_level;
+       br->curr = level = max_level;
+
+       if (!device->cap._BQC)
+               goto set_level;
+
        result = acpi_video_device_lcd_get_level_current(device, &level_old);
        if (result)
                goto out_free_levels;
 
-       result = acpi_video_device_lcd_set_level(device, br->curr);
+       /*
+        * Set the level to maximum and check if _BQC uses indexed value
+        */
+       result = acpi_video_device_lcd_set_level(device, max_level);
        if (result)
                goto out_free_levels;
 
@@ -806,26 +900,30 @@ acpi_video_init_brightness(struct acpi_video_device *device)
        if (result)
                goto out_free_levels;
 
-       if ((level != level_old) && !br->flags._BCM_use_index) {
-               /* Note:
-                * This piece of code does not work correctly if the current
-                * brightness levels is 0.
-                * But I guess boxes that boot with such a dark screen are rare
-                * and no more code is needed to cover this specifial case.
-                */
+       br->flags._BQC_use_index = (level == max_level ? 0 : 1);
 
-               if (level_ac_battery != 2) {
-                       /*
-                        * For now, we don't support the _BCL like this:
-                        * 16, 15, 0, 1, 2, 3, ..., 14, 15, 16
-                        * because we may mess up the index returned by _BQC.
-                        * Plus: we have not got a box like this.
-                        */
-                       ACPI_ERROR((AE_INFO, "_BCL not supported\n"));
-               }
-               br->flags._BQC_use_index = 1;
+       if (!br->flags._BQC_use_index) {
+               /*
+                * Set the backlight to the initial state.
+                * On some buggy laptops, _BQC returns an uninitialized value
+                * when invoked for the first time, i.e. level_old is invalid.
+                * set the backlight to max_level in this case
+                */
+               for (i = 2; i < br->count; i++)
+                       if (level_old == br->levels[i])
+                               level = level_old;
+               goto set_level;
        }
 
+       if (br->flags._BCL_reversed)
+               level_old = (br->count - 1) - level_old;
+       level = br->levels[level_old];
+
+set_level:
+       result = acpi_video_device_lcd_set_level(device, level);
+       if (result)
+               goto out_free_levels;
+
        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "found %d brightness levels\n", count - 2));
        kfree(obj);
@@ -856,9 +954,6 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
 {
        acpi_handle h_dummy1;
 
-
-       memset(&device->cap, 0, sizeof(device->cap));
-
        if (ACPI_SUCCESS(acpi_get_handle(device->dev->handle, "_ADR", &h_dummy1))) {
                device->cap._ADR = 1;
        }
@@ -907,19 +1002,34 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
                device->backlight->props.max_brightness = device->brightness->count-3;
                kfree(name);
 
-               device->cdev = thermal_cooling_device_register("LCD",
+               result = sysfs_create_link(&device->backlight->dev.kobj,
+                                          &device->dev->dev.kobj, "device");
+               if (result)
+                       printk(KERN_ERR PREFIX "Create sysfs link\n");
+
+               device->cooling_dev = thermal_cooling_device_register("LCD",
                                        device->dev, &video_cooling_ops);
-               if (IS_ERR(device->cdev))
+               if (IS_ERR(device->cooling_dev)) {
+                       /*
+                        * Set cooling_dev to NULL so we don't crash trying to
+                        * free it.
+                        * Also, why the hell we are returning early and
+                        * not attempt to register video output if cooling
+                        * device registration failed?
+                        * -- dtor
+                        */
+                       device->cooling_dev = NULL;
                        return;
+               }
 
                dev_info(&device->dev->dev, "registered as cooling_device%d\n",
-                        device->cdev->id);
+                        device->cooling_dev->id);
                result = sysfs_create_link(&device->dev->dev.kobj,
-                               &device->cdev->device.kobj,
+                               &device->cooling_dev->device.kobj,
                                "thermal_cooling");
                if (result)
                        printk(KERN_ERR PREFIX "Create sysfs link\n");
-               result = sysfs_create_link(&device->cdev->device.kobj,
+               result = sysfs_create_link(&device->cooling_dev->device.kobj,
                                &device->dev->dev.kobj, "device");
                if (result)
                        printk(KERN_ERR PREFIX "Create sysfs link\n");
@@ -956,7 +1066,6 @@ static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
 {
        acpi_handle h_dummy1;
 
-       memset(&video->cap, 0, sizeof(video->cap));
        if (ACPI_SUCCESS(acpi_get_handle(video->device->handle, "_DOS", &h_dummy1))) {
                video->cap._DOS = 1;
        }
@@ -985,22 +1094,27 @@ static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
 static int acpi_video_bus_check(struct acpi_video_bus *video)
 {
        acpi_status status = -ENOENT;
-       struct device *dev;
+       struct pci_dev *dev;
 
        if (!video)
                return -EINVAL;
 
-       dev = acpi_get_physical_pci_device(video->device->handle);
+       dev = acpi_get_pci_dev(video->device->handle);
        if (!dev)
                return -ENODEV;
-       put_device(dev);
+       pci_dev_put(dev);
 
        /* Since there is no HID, CID and so on for VGA driver, we have
         * to check well known required nodes.
         */
 
        /* Does this device support video switching? */
-       if (video->cap._DOS) {
+       if (video->cap._DOS || video->cap._DOD) {
+               if (!video->cap._DOS) {
+                       printk(KERN_WARNING FW_BUG
+                               "ACPI(%s) defines _DOD but not _DOS\n",
+                               acpi_device_bid(video->device));
+               }
                video->flags.multihead = 1;
                status = 0;
        }
@@ -1109,7 +1223,7 @@ acpi_video_device_write_state(struct file *file,
        u32 state = 0;
 
 
-       if (!dev || count + 1 > sizeof str)
+       if (!dev || count >= sizeof(str))
                return -EINVAL;
 
        if (copy_from_user(str, buffer, count))
@@ -1166,7 +1280,7 @@ acpi_video_device_write_brightness(struct file *file,
        int i;
 
 
-       if (!dev || !dev->brightness || count + 1 > sizeof str)
+       if (!dev || !dev->brightness || count >= sizeof(str))
                return -EINVAL;
 
        if (copy_from_user(str, buffer, count))
@@ -1244,8 +1358,6 @@ static int acpi_video_device_add_fs(struct acpi_device *device)
        if (!device_dir)
                return -ENOMEM;
 
-       device_dir->owner = THIS_MODULE;
-
        /* 'info' [R] */
        entry = proc_create_data("info", S_IRUGO, device_dir,
                        &acpi_video_device_info_fops, acpi_driver_data(device));
@@ -1253,7 +1365,6 @@ static int acpi_video_device_add_fs(struct acpi_device *device)
                goto err_remove_dir;
 
        /* 'state' [R/W] */
-       acpi_video_device_state_fops.write = acpi_video_device_write_state;
        entry = proc_create_data("state", S_IFREG | S_IRUGO | S_IWUSR,
                                 device_dir,
                                 &acpi_video_device_state_fops,
@@ -1262,8 +1373,6 @@ static int acpi_video_device_add_fs(struct acpi_device *device)
                goto err_remove_info;
 
        /* 'brightness' [R/W] */
-       acpi_video_device_brightness_fops.write =
-               acpi_video_device_write_brightness;
        entry = proc_create_data("brightness", S_IFREG | S_IRUGO | S_IWUSR,
                                 device_dir,
                                 &acpi_video_device_brightness_fops,
@@ -1453,7 +1562,7 @@ acpi_video_bus_write_POST(struct file *file,
        unsigned long long opt, options;
 
 
-       if (!video || count + 1 > sizeof str)
+       if (!video || count >= sizeof(str))
                return -EINVAL;
 
        status = acpi_video_bus_POST_options(video, &options);
@@ -1493,7 +1602,7 @@ acpi_video_bus_write_DOS(struct file *file,
        unsigned long opt;
 
 
-       if (!video || count + 1 > sizeof str)
+       if (!video || count >= sizeof(str))
                return -EINVAL;
 
        if (copy_from_user(str, buffer, count))
@@ -1522,8 +1631,6 @@ static int acpi_video_bus_add_fs(struct acpi_device *device)
        if (!device_dir)
                return -ENOMEM;
 
-       device_dir->owner = THIS_MODULE;
-
        /* 'info' [R] */
        entry = proc_create_data("info", S_IRUGO, device_dir,
                                 &acpi_video_bus_info_fops,
@@ -1546,7 +1653,6 @@ static int acpi_video_bus_add_fs(struct acpi_device *device)
                goto err_remove_rom;
 
        /* 'POST' [R/W] */
-       acpi_video_bus_POST_fops.write = acpi_video_bus_write_POST;
        entry = proc_create_data("POST", S_IFREG | S_IRUGO | S_IWUSR,
                                 device_dir,
                                 &acpi_video_bus_POST_fops,
@@ -1555,7 +1661,6 @@ static int acpi_video_bus_add_fs(struct acpi_device *device)
                goto err_remove_post_info;
 
        /* 'DOS' [R/W] */
-       acpi_video_bus_DOS_fops.write = acpi_video_bus_write_DOS;
        entry = proc_create_data("DOS", S_IFREG | S_IRUGO | S_IWUSR,
                                 device_dir,
                                 &acpi_video_bus_DOS_fops,
@@ -1886,6 +1991,10 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event)
 
        result = acpi_video_device_lcd_set_level(device, level_next);
 
+       if (!result)
+               backlight_force_update(device->backlight,
+                                      BACKLIGHT_UPDATE_HOTKEY);
+
 out:
        if (result)
                printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
@@ -1930,14 +2039,18 @@ static int acpi_video_bus_put_one_device(struct acpi_video_device *device)
        status = acpi_remove_notify_handler(device->dev->handle,
                                            ACPI_DEVICE_NOTIFY,
                                            acpi_video_device_notify);
-       backlight_device_unregister(device->backlight);
-       if (device->cdev) {
+       if (device->backlight) {
+               sysfs_remove_link(&device->backlight->dev.kobj, "device");
+               backlight_device_unregister(device->backlight);
+               device->backlight = NULL;
+       }
+       if (device->cooling_dev) {
                sysfs_remove_link(&device->dev->dev.kobj,
                                  "thermal_cooling");
-               sysfs_remove_link(&device->cdev->device.kobj,
+               sysfs_remove_link(&device->cooling_dev->device.kobj,
                                  "device");
-               thermal_cooling_device_unregister(device->cdev);
-               device->cdev = NULL;
+               thermal_cooling_device_unregister(device->cooling_dev);
+               device->cooling_dev = NULL;
        }
        video_output_unregister(device->output_dev);
 
@@ -1983,17 +2096,15 @@ static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
        return acpi_video_bus_DOS(video, 0, 1);
 }
 
-static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data)
+static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
 {
-       struct acpi_video_bus *video = data;
-       struct acpi_device *device = NULL;
+       struct acpi_video_bus *video = acpi_driver_data(device);
        struct input_dev *input;
        int keycode;
 
        if (!video)
                return;
 
-       device = video->device;
        input = video->input;
 
        switch (event) {
@@ -2124,7 +2235,6 @@ static int acpi_video_resume(struct acpi_device *device)
 
 static int acpi_video_bus_add(struct acpi_device *device)
 {
-       acpi_status status;
        struct acpi_video_bus *video;
        struct input_dev *input;
        int error;
@@ -2166,20 +2276,10 @@ static int acpi_video_bus_add(struct acpi_device *device)
        acpi_video_bus_get_devices(video, device);
        acpi_video_bus_start_devices(video);
 
-       status = acpi_install_notify_handler(device->handle,
-                                            ACPI_DEVICE_NOTIFY,
-                                            acpi_video_bus_notify, video);
-       if (ACPI_FAILURE(status)) {
-               printk(KERN_ERR PREFIX
-                                 "Error installing notify handler\n");
-               error = -ENODEV;
-               goto err_stop_video;
-       }
-
        video->input = input = input_allocate_device();
        if (!input) {
                error = -ENOMEM;
-               goto err_uninstall_notify;
+               goto err_stop_video;
        }
 
        snprintf(video->phys, sizeof(video->phys),
@@ -2215,9 +2315,6 @@ static int acpi_video_bus_add(struct acpi_device *device)
 
  err_free_input_dev:
        input_free_device(input);
- err_uninstall_notify:
-       acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
-                                  acpi_video_bus_notify);
  err_stop_video:
        acpi_video_bus_stop_devices(video);
        acpi_video_bus_put_devices(video);
@@ -2232,7 +2329,6 @@ static int acpi_video_bus_add(struct acpi_device *device)
 
 static int acpi_video_bus_remove(struct acpi_device *device, int type)
 {
-       acpi_status status = 0;
        struct acpi_video_bus *video = NULL;
 
 
@@ -2242,11 +2338,6 @@ static int acpi_video_bus_remove(struct acpi_device *device, int type)
        video = acpi_driver_data(device);
 
        acpi_video_bus_stop_devices(video);
-
-       status = acpi_remove_notify_handler(video->device->handle,
-                                           ACPI_DEVICE_NOTIFY,
-                                           acpi_video_bus_notify);
-
        acpi_video_bus_put_devices(video);
        acpi_video_bus_remove_fs(device);
 
@@ -2280,11 +2371,17 @@ static int __init intel_opregion_present(void)
 int acpi_video_register(void)
 {
        int result = 0;
+       if (register_count) {
+               /*
+                * if the function of acpi_video_register is already called,
+                * don't register the acpi_vide_bus again and return no error.
+                */
+               return 0;
+       }
 
        acpi_video_dir = proc_mkdir(ACPI_VIDEO_CLASS, acpi_root_dir);
        if (!acpi_video_dir)
                return -ENODEV;
-       acpi_video_dir->owner = THIS_MODULE;
 
        result = acpi_bus_register_driver(&acpi_video_bus);
        if (result < 0) {
@@ -2292,10 +2389,35 @@ int acpi_video_register(void)
                return -ENODEV;
        }
 
+       /*
+        * When the acpi_video_bus is loaded successfully, increase
+        * the counter reference.
+        */
+       register_count = 1;
+
        return 0;
 }
 EXPORT_SYMBOL(acpi_video_register);
 
+void acpi_video_unregister(void)
+{
+       if (!register_count) {
+               /*
+                * If the acpi video bus is already unloaded, don't
+                * unload it again and return directly.
+                */
+               return;
+       }
+       acpi_bus_unregister_driver(&acpi_video_bus);
+
+       remove_proc_entry(ACPI_VIDEO_CLASS, acpi_root_dir);
+
+       register_count = 0;
+
+       return;
+}
+EXPORT_SYMBOL(acpi_video_unregister);
+
 /*
  * This is kind of nasty. Hardware using Intel chipsets may require
  * the video opregion code to be run first in order to initialise
@@ -2305,6 +2427,8 @@ EXPORT_SYMBOL(acpi_video_register);
 
 static int __init acpi_video_init(void)
 {
+       dmi_check_system(video_dmi_table);
+
        if (intel_opregion_present())
                return 0;
 
@@ -2313,10 +2437,7 @@ static int __init acpi_video_init(void)
 
 static void __exit acpi_video_exit(void)
 {
-
-       acpi_bus_unregister_driver(&acpi_video_bus);
-
-       remove_proc_entry(ACPI_VIDEO_CLASS, acpi_root_dir);
+       acpi_video_unregister();
 
        return;
 }