[src/trunk]: src/sys/dev/acpi Add a new flag that determines whether we shoul...

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

details:   https://anonhg.NetBSD.org/src/rev/56e153d7318d
branches:  trunk
changeset: 756557:56e153d7318d
user:      jruoho <jruoho%NetBSD.org@localhost>
date:      Fri Jul 23 08:11:49 2010 +0000

description:
Add a new flag that determines whether we should check for bus master
activity (BM_STS) by reading from the PM1 register. According to the Intel
processor specification for ACPI, the FFH GAS encoding may provide a hint
that the check is not required. This may help some systems to enter C2/C3
even when e.g. usb(4) keeps the BM_STS bit always enabled.

diffstat:

 sys/dev/acpi/acpi_cpu.h        |  21 +++++++++++++--------
 sys/dev/acpi/acpi_cpu_cstate.c |  34 ++++++++++++++++++++++++----------
 2 files changed, 37 insertions(+), 18 deletions(-)

diffs (141 lines):

diff -r f9654314b60e -r 56e153d7318d sys/dev/acpi/acpi_cpu.h
--- a/sys/dev/acpi/acpi_cpu.h   Fri Jul 23 05:32:02 2010 +0000
+++ b/sys/dev/acpi/acpi_cpu.h   Fri Jul 23 08:11:49 2010 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: acpi_cpu.h,v 1.4 2010/07/23 05:32:02 jruoho Exp $ */
+/* $NetBSD: acpi_cpu.h,v 1.5 2010/07/23 08:11:49 jruoho Exp $ */
 
 /*-
  * Copyright (c) 2010 Jukka Ruohonen <jruohonen%iki.fi@localhost>
@@ -53,6 +53,12 @@
 #define ACPICPU_PDC_P_HW          __BIT(11)    /* Px hardware coordination  */
 
 /*
+ * See ibid., table 4.
+ */
+#define ACPICPU_PDC_GAS_HW       __BIT(0)      /* hw-coordinated state      */
+#define ACPICPU_PDC_GAS_BM       __BIT(1)      /* bus master check required */
+
+/*
  * Notify values.
  */
 #define ACPICPU_P_NOTIFY        0x80           /* _PPC */
@@ -73,19 +79,17 @@
 #define ACPICPU_C_STATE_FFH     0x02
 #define ACPICPU_C_STATE_SYSIO   0x03
 
-/*
- * Global flags in the softc.
- */
 #define ACPICPU_FLAG_C          __BIT(0)
 #define ACPICPU_FLAG_P          __BIT(1)
 #define ACPICPU_FLAG_T          __BIT(2)
 #define ACPICPU_FLAG_C_CST      __BIT(3)
 #define ACPICPU_FLAG_C_FADT     __BIT(4)
 #define ACPICPU_FLAG_C_BM       __BIT(5)
-#define ACPICPU_FLAG_C_ARB      __BIT(6)
-#define ACPICPU_FLAG_C_NOC3     __BIT(7)
-#define ACPICPU_FLAG_C_MWAIT    __BIT(8)
-#define ACPICPU_FLAG_C_C1E      __BIT(9)
+#define ACPICPU_FLAG_C_BM_STS   __BIT(6)
+#define ACPICPU_FLAG_C_ARB      __BIT(7)
+#define ACPICPU_FLAG_C_NOC3     __BIT(8)
+#define ACPICPU_FLAG_C_MWAIT    __BIT(9)
+#define ACPICPU_FLAG_C_C1E      __BIT(10)
 
 struct acpicpu_cstate {
        uint64_t                 cs_stat;
@@ -93,6 +97,7 @@
        uint32_t                 cs_power;      /* mW */
        uint32_t                 cs_latency;    /* us */
        int                      cs_method;
+       int                      cs_flags;
 };
 
 struct acpicpu_csd {
diff -r f9654314b60e -r 56e153d7318d sys/dev/acpi/acpi_cpu_cstate.c
--- a/sys/dev/acpi/acpi_cpu_cstate.c    Fri Jul 23 05:32:02 2010 +0000
+++ b/sys/dev/acpi/acpi_cpu_cstate.c    Fri Jul 23 08:11:49 2010 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: acpi_cpu_cstate.c,v 1.6 2010/07/23 05:32:02 jruoho Exp $ */
+/* $NetBSD: acpi_cpu_cstate.c,v 1.7 2010/07/23 08:11:49 jruoho Exp $ */
 
 /*-
  * Copyright (c) 2010 Jukka Ruohonen <jruohonen%iki.fi@localhost>
@@ -27,7 +27,7 @@
  * SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_cpu_cstate.c,v 1.6 2010/07/23 05:32:02 jruoho Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_cpu_cstate.c,v 1.7 2010/07/23 08:11:49 jruoho Exp $");
 
 #include <sys/param.h>
 #include <sys/cpu.h>
@@ -171,8 +171,9 @@
                }
 
                aprint_debug_dev(sc->sc_dev, "C%d: %5s, "
-                   "latency %4u, power %4u, addr 0x%06x\n", i, method,
-                   cs->cs_latency, cs->cs_power, (uint32_t)cs->cs_addr);
+                   "latency %4u, power %4u, addr 0x%06x, flags 0x%02x\n",
+                   i, method, cs->cs_latency, cs->cs_power,
+                   (uint32_t)cs->cs_addr, cs->cs_flags);
        }
 }
 
@@ -336,6 +337,8 @@
 
        (void)memset(&state, 0, sizeof(*cs));
 
+       state.cs_flags = ACPICPU_FLAG_C_BM_STS;
+
        if (elm->Type != ACPI_TYPE_PACKAGE) {
                rv = AE_TYPE;
                goto out;
@@ -456,6 +459,16 @@
                        }
                }
 
+               if (sc->sc_cap != 0) {
+
+                       /*
+                        * The _CST FFH GAS encoding may contain
+                        * additional hints on Intel processors.
+                        */
+                       if ((reg->reg_accesssize & ACPICPU_PDC_GAS_BM) == 0)
+                               state.cs_flags &= ~ACPICPU_FLAG_C_BM_STS;
+               }
+
                break;
 
        default:
@@ -483,8 +496,9 @@
 
        cs[type].cs_addr = state.cs_addr;
        cs[type].cs_power = state.cs_power;
+       cs[type].cs_flags = state.cs_flags;
+       cs[type].cs_method = state.cs_method;
        cs[type].cs_latency = state.cs_latency;
-       cs[type].cs_method = state.cs_method;
 
 out:
        if (ACPI_FAILURE(rv))
@@ -733,13 +747,13 @@
        state = acpicpu_cstate_latency(sc);
 
        /*
-        * Check for bus master activity. Note that
-        * particularly usb(4) causes high activity,
-        * which may prevent the use of C3 states.
+        * Check for bus master activity. Note that particularly usb(4)
+        * causes high activity, which may prevent the use of C3 states.
         */
-       if (acpicpu_cstate_bm_check() != false) {
+       if ((sc->sc_cstate[state].cs_flags & ACPICPU_FLAG_C_BM_STS) != 0) {
 
-               state--;
+               if (acpicpu_cstate_bm_check() != false)
+                       state--;
 
                if (__predict_false(sc->sc_cstate[state].cs_method == 0))
                        state = ACPI_STATE_C1;