Some x86 machines advertise the "hardware reduced" ACPI feature, advertise

S4 and S5 support, but fail to populate the SLEEP_CONTROL_REG and
SLEEP_STATUS_REG descriptions in the FADT.  An example of such a machine
is the ASUS Zenbook 14 UM433DA.  Any attempt to powerdown the machine
will result in a kernel crash.  It turns out that using the legacy ACPI PM
registers works fine on this machien.  So fall back on those registers
if SLEEP_CONTROL_REG and/or SLEEP_STATUS_REG aren't provided.

ok deraadt@, mpi@

diff --git a/sys/dev/acpi/acpi.c b/sys/dev/acpi/acpi.c
index f39e923..51753fc 100644 (file)
--- a/sys/dev/acpi/acpi.c
+++ b/sys/dev/acpi/acpi.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: acpi.c,v 1.397 2021/03/15 22:44:57 patrick Exp $ */
+/* $OpenBSD: acpi.c,v 1.398 2021/05/09 15:51:35 kettenis Exp $ */
 /*
  * Copyright (c) 2005 Thorsten Lockert <tholo@sigmasoft.com>
  * Copyright (c) 2005 Jordan Hargrave <jordan@openbsd.org>
@@ -1436,7 +1436,8 @@ acpi_read_pmreg(struct acpi_softc *sc, int reg, int offset)
         * For Hardware-reduced ACPI we also emulate PM1A_STS using
         * SLEEP_STATUS_REG.
         */
-       if (sc->sc_hw_reduced && reg == ACPIREG_PM1A_STS) {
+       if (sc->sc_hw_reduced && reg == ACPIREG_PM1A_STS &&
+           sc->sc_fadt->sleep_status_reg.register_bit_width > 0) {
                uint8_t value;
 
                KASSERT(offset == 0);
@@ -1514,7 +1515,8 @@ acpi_write_pmreg(struct acpi_softc *sc, int reg, int offset, int regval)
         * For Hardware-reduced ACPI we also emulate PM1A_STS using
         * SLEEP_STATUS_REG.
         */
-       if (sc->sc_hw_reduced && reg == ACPIREG_PM1A_STS) {
+       if (sc->sc_hw_reduced && reg == ACPIREG_PM1A_STS &&
+           sc->sc_fadt->sleep_status_reg.register_bit_width > 0) {
                uint8_t value = (regval >> 8);
 
                KASSERT(offset == 0);
@@ -1530,7 +1532,8 @@ acpi_write_pmreg(struct acpi_softc *sc, int reg, int offset, int regval)
         * For Hardware-reduced ACPI we also emulate PM1A_CNT using
         * SLEEP_CONTROL_REG.
         */
-       if (sc->sc_hw_reduced && reg == ACPIREG_PM1A_CNT) {
+       if (sc->sc_hw_reduced && reg == ACPIREG_PM1A_CNT &&
+           sc->sc_fadt->sleep_control_reg.register_bit_width > 0) {
                uint8_t value = (regval >> 8);
 
                KASSERT(offset == 0);
@@ -1609,10 +1612,6 @@ acpi_map_pmregs(struct acpi_softc *sc)
        const char *name;
        int reg;
 
-       /* Registers don't exist on Hardware-reduced ACPI. */
-       if (sc->sc_hw_reduced)
-               return;
-
        for (reg = 0; reg < ACPIREG_MAXREG; reg++) {
                size = 0;
                access = 0;