[ASUS_ACPI] work around Samsung P30s oops

The code used to rely on a certain method to return a NULL buffer, which
is now hardly possible with the implicit return code on by default. This
sort of fixes bugs #5067 and #5092 for now.

Note: this patch makes the driver unusable on said machines (and on said
machines only) iff acpi=strict is specified, but it seems noone really uses
that.

Signed-off-by: Karol Kozimor <sziwan@hell.org.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 18 insertions, 9 deletions

diff --git a/drivers/acpi/asus_acpi.c b/drivers/acpi/asus_acpi.c
index fec895af6ae6..582995ef9f34 100644
--- a/drivers/acpi/asus_acpi.c
+++ b/drivers/acpi/asus_acpi.c
@@ -987,9 +987,21 @@ static int __init asus_hotk_get_info(void)
                 printk(KERN_NOTICE "  BSTS called, 0x%02x returned\n",
                        bsts_result);
 
-        /* Samsung P30 has a device with a valid _HID whose INIT does not 
-         * return anything. Catch this one and any similar here */
-        if (buffer.pointer == NULL) {
+        /* This is unlikely with implicit return */
+        if (buffer.pointer == NULL)
+                return -EINVAL;
+
+        model = (union acpi_object *) buffer.pointer;
+        /*
+         * Samsung P30 has a device with a valid _HID whose INIT does not 
+         * return anything. It used to be possible to catch this exception,
+         * but the implicit return code will now happily confuse the 
+         * driver. We assume that every ACPI_TYPE_STRING is a valid model
+         * identifier but it's still possible to get completely bogus data.
+         */
+        if (model->type == ACPI_TYPE_STRING) {
+                printk(KERN_NOTICE "  %s model detected, ", model->string.pointer);
+        } else {
                 if (asus_info &&        /* Samsung P30 */
                     strncmp(asus_info->oem_table_id, "ODEM", 4) == 0) {
                         hotk->model = P30;
@@ -1002,13 +1014,10 @@ static int __init asus_hotk_get_info(void)
                                "the developers with your DSDT\n");
                 }
                 hotk->methods = &model_conf[hotk->model];
-                return AE_OK;
-        }
+                
+                acpi_os_free(model);
 
-        model = (union acpi_object *)buffer.pointer;
-        if (model->type == ACPI_TYPE_STRING) {
-                printk(KERN_NOTICE "  %s model detected, ",
-                       model->string.pointer);
+                return AE_OK;
         }
 
         hotk->model = END_MODEL;