diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 9cc769b..215f1bf7 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -479,6 +479,13 @@
 		goto end;
 	}
 
+	if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
+	    pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
+	    pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
+		printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
+		result = -EFAULT;
+		goto end;
+	}
 end:
 	kfree(buffer.pointer);
 	return result;
@@ -501,9 +508,10 @@
 
 	mutex_lock(&performance_mutex);
 
-	retval = 0;
-
-	/* Call _PSD for all CPUs */
+	/*
+	 * Check if another driver has already registered, and abort before
+	 * changing pr->performance if it has. Check input data as well.
+	 */
 	for_each_possible_cpu(i) {
 		pr = per_cpu(processors, i);
 		if (!pr) {
@@ -513,13 +521,20 @@
 
 		if (pr->performance) {
 			retval = -EBUSY;
-			continue;
+			goto err_out;
 		}
 
 		if (!performance || !percpu_ptr(performance, i)) {
 			retval = -EINVAL;
-			continue;
+			goto err_out;
 		}
+	}
+
+	/* Call _PSD for all CPUs */
+	for_each_possible_cpu(i) {
+		pr = per_cpu(processors, i);
+		if (!pr)
+			continue;
 
 		pr->performance = percpu_ptr(performance, i);
 		cpumask_set_cpu(i, pr->performance->shared_cpu_map);
@@ -535,26 +550,6 @@
 	 * Now that we have _PSD data from all CPUs, lets setup P-state 
 	 * domain info.
 	 */
-	for_each_possible_cpu(i) {
-		pr = per_cpu(processors, i);
-		if (!pr)
-			continue;
-
-		/* Basic validity check for domain info */
-		pdomain = &(pr->performance->domain_info);
-		if ((pdomain->revision != ACPI_PSD_REV0_REVISION) ||
-		    (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES)) {
-			retval = -EINVAL;
-			goto err_ret;
-		}
-		if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
-		    pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
-		    pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
-			retval = -EINVAL;
-			goto err_ret;
-		}
-	}
-
 	cpumask_clear(covered_cpus);
 	for_each_possible_cpu(i) {
 		pr = per_cpu(processors, i);
@@ -643,6 +638,7 @@
 		pr->performance = NULL; /* Will be set for real in register */
 	}
 
+err_out:
 	mutex_unlock(&performance_mutex);
 	free_cpumask_var(covered_cpus);
 	return retval;