[src/trunk]: src/sys/dev/acpi Error out if we try to set power to a higher-po...

[jruoho <jruoho%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ab23adeea543
branches:  trunk
changeset: 755535:ab23adeea543
user:      jruoho <jruoho%NetBSD.org@localhost>
date:      Tue Jun 08 18:18:24 2010 +0000

description:
Error out if we try to set power to a higher-power state than the parent's
state. This follows the "bus power state" -logic noted in the spec:

        bus: D1
                device A : D1 -> D0 -> error
                device B : D1 -> D2 -> success

                -> bus must remain in D1 due device A

Following this scheme, it is easy to derive the "bus power state" now that
we have the device nodes in a tree-like structure. If required, separate
acpi_power_get_bus() and acpi_power_set_bus() can be added in the future.

diffstat:

 sys/dev/acpi/acpi_power.c |  19 +++++++++++++++----
 1 files changed, 15 insertions(+), 4 deletions(-)

diffs (47 lines):

diff -r f31b65d4fee4 -r ab23adeea543 sys/dev/acpi/acpi_power.c
--- a/sys/dev/acpi/acpi_power.c Tue Jun 08 18:04:17 2010 +0000
+++ b/sys/dev/acpi/acpi_power.c Tue Jun 08 18:18:24 2010 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: acpi_power.c,v 1.17 2010/06/07 17:28:17 jruoho Exp $ */
+/* $NetBSD: acpi_power.c,v 1.18 2010/06/08 18:18:24 jruoho Exp $ */
 
 /*-
  * Copyright (c) 2009, 2010 The NetBSD Foundation, Inc.
@@ -56,7 +56,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_power.c,v 1.17 2010/06/07 17:28:17 jruoho Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_power.c,v 1.18 2010/06/08 18:18:24 jruoho Exp $");
 
 #include <sys/param.h>
 #include <sys/kmem.h>
@@ -395,6 +395,17 @@
        }
 
        /*
+        * As noted in ACPI 4.0 (appendix A.2.1), the bus power state
+        * should never be lower than the highest state of one of its
+        * devices. Consequently, we cannot set the state to a lower
+        * (i.e. higher power) state than the parent device's state.
+        */
+       if (ad->ad_parent != NULL && ad->ad_parent->ad_state > state) {
+               rv = AE_ABORT_METHOD;
+               goto fail;
+       }
+
+       /*
         * We first sweep through the resources required for the target
         * state, turning things on and building references. After this
         * we dereference the resources required for the current state,
@@ -418,8 +429,8 @@
        (void)snprintf(path, sizeof(path), "_PS%d", state);
        (void)AcpiEvaluateObject(ad->ad_handle, path, NULL, NULL);
 
-       aprint_debug_dev(ad->ad_root, "%s turned from "
-           "D%d to D%d\n", ad->ad_name, old, state);
+       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s turned from "
+               "D%d to D%d\n", ad->ad_name, old, state));
 
        ad->ad_state = state;