ACPI: video: fix brightness allocation

Fix use of uninitialized device->brightness.

Signed-off-by: Julia Jomantaite <julia.jomantaite@gmail.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 73 insertions, 50 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index d089c4519d45..64c889331f3b 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -631,6 +631,76 @@ acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
  *      device  : video output device (LCD, CRT, ..)
  *
  *  Return Value:
+ *      Maximum brightness level
+ *
+ *  Allocate and initialize device->brightness.
+ */
+
+static int
+acpi_video_init_brightness(struct acpi_video_device *device)
+{
+        union acpi_object *obj = NULL;
+        int i, max_level = 0, count = 0;
+        union acpi_object *o;
+        struct acpi_video_device_brightness *br = NULL;
+
+        if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
+                                                "LCD brightness level\n"));
+                goto out;
+        }
+
+        if (obj->package.count < 2)
+                goto out;
+
+        br = kzalloc(sizeof(*br), GFP_KERNEL);
+        if (!br) {
+                printk(KERN_ERR "can't allocate memory\n");
+                goto out;
+        }
+
+        br->levels = kmalloc(obj->package.count * sizeof *(br->levels),
+                                GFP_KERNEL);
+        if (!br->levels)
+                goto out_free;
+
+        for (i = 0; i < obj->package.count; i++) {
+                o = (union acpi_object *)&obj->package.elements[i];
+                if (o->type != ACPI_TYPE_INTEGER) {
+                        printk(KERN_ERR PREFIX "Invalid data\n");
+                        continue;
+                }
+                br->levels[count] = (u32) o->integer.value;
+
+                if (br->levels[count] > max_level)
+                        max_level = br->levels[count];
+                count++;
+        }
+
+        if (count < 2)
+                goto out_free_levels;
+
+        br->count = count;
+        device->brightness = br;
+        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "found %d brightness levels\n", count));
+        kfree(obj);
+        return max_level;
+
+out_free_levels:
+        kfree(br->levels);
+out_free:
+        kfree(br);
+out:
+        device->brightness = NULL;
+        kfree(obj);
+        return 0;
+}
+
+/*
+ *  Arg:
+ *      device  : video output device (LCD, CRT, ..)
+ *
+ *  Return Value:
  *      None
  *
  *  Find out all required AML methods defined under the output
@@ -640,10 +710,7 @@ acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 static void acpi_video_device_find_cap(struct acpi_video_device *device)
 {
         acpi_handle h_dummy1;
-        int i;
         u32 max_level = 0;
-        union acpi_object *obj = NULL;
-        struct acpi_video_device_brightness *br = NULL;
 
 
         memset(&device->cap, 0, sizeof(device->cap));
@@ -672,53 +739,7 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
                 device->cap._DSS = 1;
         }
 
-        if (ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
-
-                if (obj->package.count >= 2) {
-                        int count = 0;
-                        union acpi_object *o;
-
-                        br = kzalloc(sizeof(*br), GFP_KERNEL);
-                        if (!br) {
-                                printk(KERN_ERR "can't allocate memory\n");
-                        } else {
-                                br->levels = kmalloc(obj->package.count *
-                                                     sizeof *(br->levels), GFP_KERNEL);
-                                if (!br->levels)
-                                        goto out;
-
-                                for (i = 0; i < obj->package.count; i++) {
-                                        o = (union acpi_object *)&obj->package.
-                                            elements[i];
-                                        if (o->type != ACPI_TYPE_INTEGER) {
-                                                printk(KERN_ERR PREFIX "Invalid data\n");
-                                                continue;
-                                        }
-                                        br->levels[count] = (u32) o->integer.value;
-
-                                        if (br->levels[count] > max_level)
-                                                max_level = br->levels[count];
-                                        count++;
-                                }
-                              out:
-                                if (count < 2) {
-                                        kfree(br->levels);
-                                        kfree(br);
-                                } else {
-                                        br->count = count;
-                                        device->brightness = br;
-                                        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-                                                          "found %d brightness levels\n",
-                                                          count));
-                                }
-                        }
-                }
-
-        } else {
-                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available LCD brightness level\n"));
-        }
-
-        kfree(obj);
+        max_level = acpi_video_init_brightness(device);
 
         if (device->cap._BCL && device->cap._BCM && device->cap._BQC && max_level > 0){
                 int result;
@@ -1695,6 +1716,8 @@ static void
 acpi_video_switch_brightness(struct acpi_video_device *device, int event)
 {
         unsigned long level_current, level_next;
+        if (!device->brightness)
+                return;
         acpi_video_device_lcd_get_level_current(device, &level_current);
         level_next = acpi_video_get_next_level(device, level_current, event);
         acpi_video_device_lcd_set_level(device, level_next);