1 files changed, 24 insertions, 30 deletions

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index f68a4ffd3..c0cfd3a3e 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -630,33 +630,6 @@ int pcc_data_alloc(int pcc_ss_id)
 	return 0;
 }
 
-/* Check if CPPC revision + num_ent combination is supported */
-static bool is_cppc_supported(int revision, int num_ent)
-{
-	int expected_num_ent;
-
-	switch (revision) {
-	case CPPC_V2_REV:
-		expected_num_ent = CPPC_V2_NUM_ENT;
-		break;
-	case CPPC_V3_REV:
-		expected_num_ent = CPPC_V3_NUM_ENT;
-		break;
-	default:
-		pr_debug("Firmware exports unsupported CPPC revision: %d\n",
-			revision);
-		return false;
-	}
-
-	if (expected_num_ent != num_ent) {
-		pr_debug("Firmware exports %d entries. Expected: %d for CPPC rev:%d\n",
-			num_ent, expected_num_ent, revision);
-		return false;
-	}
-
-	return true;
-}
-
 /*
  * An example CPC table looks like the following.
  *
@@ -752,7 +725,6 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 				cpc_obj->type);
 		goto out_free;
 	}
-	cpc_ptr->num_entries = num_ent;
 
 	/* Second entry should be revision. */
 	cpc_obj = &out_obj->package.elements[1];
@@ -763,10 +735,32 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 				cpc_obj->type);
 		goto out_free;
 	}
-	cpc_ptr->version = cpc_rev;
 
-	if (!is_cppc_supported(cpc_rev, num_ent))
+	if (cpc_rev < CPPC_V2_REV) {
+		pr_debug("Unsupported _CPC Revision (%d) for CPU:%d\n", cpc_rev,
+			 pr->id);
 		goto out_free;
+	}
+
+	/*
+	 * Disregard _CPC if the number of entries in the return pachage is not
+	 * as expected, but support future revisions being proper supersets of
+	 * the v3 and only causing more entries to be returned by _CPC.
+	 */
+	if ((cpc_rev == CPPC_V2_REV && num_ent != CPPC_V2_NUM_ENT) ||
+	    (cpc_rev == CPPC_V3_REV && num_ent != CPPC_V3_NUM_ENT) ||
+	    (cpc_rev > CPPC_V3_REV && num_ent <= CPPC_V3_NUM_ENT)) {
+		pr_debug("Unexpected number of _CPC return package entries (%d) for CPU:%d\n",
+			 num_ent, pr->id);
+		goto out_free;
+	}
+	if (cpc_rev > CPPC_V3_REV) {
+		num_ent = CPPC_V3_NUM_ENT;
+		cpc_rev = CPPC_V3_REV;
+	}
+
+	cpc_ptr->num_entries = num_ent;
+	cpc_ptr->version = cpc_rev;
 
 	/* Iterate through remaining entries in _CPC */
 	for (i = 2; i < num_ent; i++) {