ACPI: EC: Add some basic check for ECDT data

One more ASUS comes with empty ECDT, add a guard for it...

http://bugzilla.kernel.org/show_bug.cgi?id=11880

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 22 insertions, 21 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index cf41f9fc24a7..3ba034fffda5 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -977,7 +977,6 @@ static const struct acpi_device_id ec_device_ids[] = {
 
 int __init acpi_ec_ecdt_probe(void)
 {
-        int ret;
         acpi_status status;
         struct acpi_table_ecdt *ecdt_ptr;
 
@@ -1005,30 +1004,32 @@ int __init acpi_ec_ecdt_probe(void)
                 boot_ec->gpe = ecdt_ptr->gpe;
                 boot_ec->handle = ACPI_ROOT_OBJECT;
                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
-        } else {
-                /* This workaround is needed only on some broken machines,
-                 * which require early EC, but fail to provide ECDT */
-                acpi_handle x;
-                printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
-                status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
-                                                boot_ec, NULL);
-                /* Check that acpi_get_devices actually find something */
-                if (ACPI_FAILURE(status) || !boot_ec->handle)
-                        goto error;
-                /* We really need to limit this workaround, the only ASUS,
-                 * which needs it, has fake EC._INI method, so use it as flag.
-                 * Keep boot_ec struct as it will be needed soon.
-                 */
-                if (ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI", &x)))
-                        return -ENODEV;
+                /* Add some basic check against completely broken table */
+                if (boot_ec->data_addr != boot_ec->command_addr)
+                        goto install;
+        /* fall through */
         }
-
-        ret = ec_install_handlers(boot_ec);
-        if (!ret) {
+        /* This workaround is needed only on some broken machines,
+         * which require early EC, but fail to provide ECDT */
+        acpi_handle x;
+        printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
+        status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
+                                        boot_ec, NULL);
+        /* Check that acpi_get_devices actually find something */
+        if (ACPI_FAILURE(status) || !boot_ec->handle)
+                goto error;
+        /* We really need to limit this workaround, the only ASUS,
+         * which needs it, has fake EC._INI method, so use it as flag.
+         * Keep boot_ec struct as it will be needed soon.
+         */
+        if (ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI", &x)))
+                return -ENODEV;
+install:
+        if (!ec_install_handlers(boot_ec)) {
                 first_ec = boot_ec;
                 return 0;
         }
-      error:
+error:
         kfree(boot_ec);
         boot_ec = NULL;
         return -ENODEV;