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Subject[patch 19/23] ACPI: video: fix brightness allocation

2.6.26-stable review patch. If anyone has any objections, please let us know.

------------------
From: Julia Jomantaite <julia.jomantaite@gmail.com>

upstream commit 469778c1740fcf3113498b6fdf4559bdec25c58f

Thanks to Arjan for spotting this
http://www.kerneloops.org/search.php?search=acpi_video_switch_brightness
and suggesting it for .stable


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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/acpi/video.c | 123 ++++++++++++++++++++++++++++++---------------------
1 file changed, 73 insertions(+), 50 deletions(-)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -631,6 +631,76 @@ acpi_video_bus_DOS(struct acpi_video_bus
* 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
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(s
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 && max_level > 0) {
int result;
@@ -1705,6 +1726,8 @@ 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);
--


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