Create C1 state when _CST is valid but _CST does not have one. Some BIOSes

do not report C1 state in _CST object, probably because it is a mandatory
state with or without existence of the optional _CST.

Reviewed by:	avg

1 files changed, 26 insertions, 4 deletions

diff --git a/sys/dev/acpica/acpi_cpu.c b/sys/dev/acpica/acpi_cpu.c
index 52934af..eb34753 100644
--- a/sys/dev/acpica/acpi_cpu.c
+++ b/sys/dev/acpica/acpi_cpu.c
@@ -668,9 +668,19 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
 	count = MAX_CX_STATES;
     }
 
-    /* Set up all valid states. */
+    sc->cpu_non_c3 = 0;
     sc->cpu_cx_count = 0;
     cx_ptr = sc->cpu_cx_states;
+
+    /*
+     * C1 has been required since just after ACPI 1.0.
+     * Reserve the first slot for it.
+     */
+    cx_ptr->type = ACPI_STATE_C0;
+    cx_ptr++;
+    sc->cpu_cx_count++;
+
+    /* Set up all valid states. */
     for (i = 0; i < count; i++) {
 	pkg = &top->Package.Elements[i + 1];
 	if (!ACPI_PKG_VALID(pkg, 4) ||
@@ -685,9 +695,14 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
 	/* Validate the state to see if we should use it. */
 	switch (cx_ptr->type) {
 	case ACPI_STATE_C1:
-	    sc->cpu_non_c3 = i;
-	    cx_ptr++;
-	    sc->cpu_cx_count++;
+	    if (sc->cpu_cx_states[0].type == ACPI_STATE_C0) {
+		/* This is the first C1 state.  Use the reserved slot. */
+		sc->cpu_cx_states[0] = *cx_ptr;
+	    } else {
+		sc->cpu_non_c3 = i;
+		cx_ptr++;
+		sc->cpu_cx_count++;
+	    }
 	    continue;
 	case ACPI_STATE_C2:
 	    sc->cpu_non_c3 = i;
@@ -726,6 +741,13 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
     }
     AcpiOsFree(buf.Pointer);
 
+    /* If C1 state was not found, we need one now. */
+    cx_ptr = sc->cpu_cx_states;
+    if (cx_ptr->type == ACPI_STATE_C0) {
+	cx_ptr->type = ACPI_STATE_C1;
+	cx_ptr->trans_lat = 0;
+    }
+
     return (0);
 }