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-rw-r--r--drivers/acpi/cppc_acpi.c54
-rw-r--r--include/acpi/cppc_acpi.h2
2 files changed, 25 insertions, 31 deletions
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 3c6d4ef87be0..1e15a9f25ae9 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -618,33 +618,6 @@ static 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.
*
@@ -733,7 +706,6 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
cpc_obj->type, pr->id);
goto out_free;
}
- cpc_ptr->num_entries = num_ent;
/* Second entry should be revision. */
cpc_obj = &out_obj->package.elements[1];
@@ -744,10 +716,32 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
cpc_obj->type, pr->id);
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++) {
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index d389bab54241..f73d357ecdf5 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -17,7 +17,7 @@
#include <acpi/pcc.h>
#include <acpi/processor.h>
-/* Support CPPCv2 and CPPCv3 */
+/* CPPCv2 and CPPCv3 support */
#define CPPC_V2_REV 2
#define CPPC_V3_REV 3
#define CPPC_V2_NUM_ENT 21