1 files changed, 18 insertions, 20 deletions

diff --git a/sys/dev/acpica/acpi_cpu.c b/sys/dev/acpica/acpi_cpu.c
index cff22a232778..bbbd23926c2c 100644
--- a/sys/dev/acpica/acpi_cpu.c
+++ b/sys/dev/acpica/acpi_cpu.c
@@ -345,28 +345,11 @@ acpi_cpu_attach(device_t dev)
     }
 
     /*
-     * CPU capabilities are specified as a buffer of 32-bit integers:
-     * revision, count, and one or more capabilities.  The revision of
-     * "1" is not specified anywhere but seems to match Linux.
+     * CPU capabilities are specified in
+     * Intel Processor Vendor-Specific ACPI Interface Specification.
      */
     if (sc->cpu_features) {
 	arglist.Pointer = arg;
-	arglist.Count = 1;
-	arg[0].Type = ACPI_TYPE_BUFFER;
-	arg[0].Buffer.Length = sizeof(cap_set);
-	arg[0].Buffer.Pointer = (uint8_t *)cap_set;
-	cap_set[0] = 1; /* revision */
-	cap_set[1] = 1; /* number of capabilities integers */
-	cap_set[2] = sc->cpu_features;
-	AcpiEvaluateObject(sc->cpu_handle, "_PDC", &arglist, NULL);
-
-	/*
-	 * On some systems we need to evaluate _OSC so that the ASL
-	 * loads the _PSS and/or _PDC methods at runtime.
-	 *
-	 * TODO: evaluate failure of _OSC.
-	 */
-	arglist.Pointer = arg;
 	arglist.Count = 4;
 	arg[0].Type = ACPI_TYPE_BUFFER;
 	arg[0].Buffer.Length = sizeof(cpu_oscuuid);
@@ -380,7 +363,22 @@ acpi_cpu_attach(device_t dev)
 	arg[3].Buffer.Pointer = (uint8_t *)cap_set;
 	cap_set[0] = 0;				/* status */
 	cap_set[1] = sc->cpu_features;
-	AcpiEvaluateObject(sc->cpu_handle, "_OSC", &arglist, NULL);
+	status = AcpiEvaluateObject(sc->cpu_handle, "_OSC", &arglist, NULL);
+	if (ACPI_SUCCESS(status)) {
+	    if (cap_set[0] != 0)
+		device_printf(dev, "_OSC returned status %#x\n", cap_set[0]);
+	}
+	else {
+	    arglist.Pointer = arg;
+	    arglist.Count = 1;
+	    arg[0].Type = ACPI_TYPE_BUFFER;
+	    arg[0].Buffer.Length = sizeof(cap_set);
+	    arg[0].Buffer.Pointer = (uint8_t *)cap_set;
+	    cap_set[0] = 1; /* revision */
+	    cap_set[1] = 1; /* number of capabilities integers */
+	    cap_set[2] = sc->cpu_features;
+	    AcpiEvaluateObject(sc->cpu_handle, "_PDC", &arglist, NULL);
+	}
     }
 
     /* Probe for Cx state support. */