Evaluate _OSC on boot to indicate our OS capabilities to ACPI. This is

needed at least to convince the BIOS to give us access to CPU freq
control on MacBooks.

Submitted by:	Rui Paulo <rpaulo / fnop.net>
Approved by:	re
MFC after:	5 days

1 files changed, 32 insertions, 7 deletions

diff --git a/sys/dev/acpica/acpi_cpu.c b/sys/dev/acpica/acpi_cpu.c
index b9a89d390ed8..324f0a430cb9 100644
--- a/sys/dev/acpica/acpi_cpu.c
+++ b/sys/dev/acpica/acpi_cpu.c
@@ -257,7 +257,7 @@ static int
 acpi_cpu_attach(device_t dev)
 {
     ACPI_BUFFER		   buf;
-    ACPI_OBJECT		   arg, *obj;
+    ACPI_OBJECT		   arg[4], *obj;
     ACPI_OBJECT_LIST	   arglist;
     struct pcpu		   *pcpu_data;
     struct acpi_cpu_softc *sc;
@@ -268,6 +268,11 @@ acpi_cpu_attach(device_t dev)
     driver_t 		  **drivers;
     uint32_t		   cap_set[3];
 
+    /* UUID needed by _OSC evaluation */
+    static uint8_t cpu_oscuuid[16] = { 0x16, 0xA6, 0x77, 0x40, 0x0C, 0x29,
+				       0xBE, 0x47, 0x9E, 0xBD, 0xD8, 0x70,
+				       0x58, 0x71, 0x39, 0x53 };
+
     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 
     sc = device_get_softc(dev);
@@ -334,19 +339,39 @@ 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.  We should
-     * also support _OSC here.
+     * "1" is not specified anywhere but seems to match Linux.
      */
     if (sc->cpu_features) {
-	arglist.Pointer = &arg;
+	arglist.Pointer = arg;
 	arglist.Count = 1;
-	arg.Type = ACPI_TYPE_BUFFER;
-	arg.Buffer.Length = sizeof(cap_set);
-	arg.Buffer.Pointer = (uint8_t *)cap_set;
+	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);
+	arg[0].Buffer.Pointer = cpu_oscuuid;	/* UUID */
+	arg[1].Type = ACPI_TYPE_INTEGER;
+	arg[1].Integer.Value = 1;		/* revision */
+	arg[2].Type = ACPI_TYPE_INTEGER;
+	arg[2].Integer.Value = 1;		/* count */
+	arg[3].Type = ACPI_TYPE_BUFFER;
+	arg[3].Buffer.Length = sizeof(cap_set);	/* Capabilities buffer */
+	arg[3].Buffer.Pointer = (uint8_t *)cap_set;
+	cap_set[0] = 0;
+	AcpiEvaluateObject(sc->cpu_handle, "_OSC", &arglist, NULL);
     }
 
     /* Probe for Cx state support. */