1 files changed, 39 insertions, 30 deletions

diff --git a/arch/x86/kernel/apic_32.c b/arch/x86/kernel/apic_32.c
index 6cb8aaaf10f5..9e8702eebd46 100644
--- a/arch/x86/kernel/apic_32.c
+++ b/arch/x86/kernel/apic_32.c
@@ -251,6 +251,9 @@ int lapic_get_maxlvt(void)
  * this function twice on the boot CPU, once with a bogus timeout
  * value, second time for real. The other (noncalibrating) CPUs
  * call this function only once, with the real, calibrated value.
+ *
+ * We do reads before writes even if unnecessary, to get around the
+ * P5 APIC double write bug.
  */
 static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen)
 {
@@ -280,6 +283,36 @@ static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen)
 }
 
 /*
+ * Setup extended LVT, AMD specific (K8, family 10h)
+ *
+ * Vector mappings are hard coded. On K8 only offset 0 (APIC500) and
+ * MCE interrupts are supported. Thus MCE offset must be set to 0.
+ */
+
+#define APIC_EILVT_LVTOFF_MCE 0
+#define APIC_EILVT_LVTOFF_IBS 1
+
+static void setup_APIC_eilvt(u8 lvt_off, u8 vector, u8 msg_type, u8 mask)
+{
+        unsigned long reg = (lvt_off << 4) + APIC_EILVT0;
+        unsigned int  v   = (mask << 16) | (msg_type << 8) | vector;
+
+        apic_write(reg, v);
+}
+
+u8 setup_APIC_eilvt_mce(u8 vector, u8 msg_type, u8 mask)
+{
+        setup_APIC_eilvt(APIC_EILVT_LVTOFF_MCE, vector, msg_type, mask);
+        return APIC_EILVT_LVTOFF_MCE;
+}
+
+u8 setup_APIC_eilvt_ibs(u8 vector, u8 msg_type, u8 mask)
+{
+        setup_APIC_eilvt(APIC_EILVT_LVTOFF_IBS, vector, msg_type, mask);
+        return APIC_EILVT_LVTOFF_IBS;
+}
+
+/*
  * Program the next event, relative to now
  */
 static int lapic_next_event(unsigned long delta,
@@ -298,7 +331,7 @@ static void lapic_timer_setup(enum clock_event_mode mode,
         unsigned long flags;
         unsigned int v;
 
-        /* Lapic used for broadcast ? */
+        /* Lapic used as dummy for broadcast ? */
         if (evt->features & CLOCK_EVT_FEAT_DUMMY)
                 return;
 
@@ -681,35 +714,6 @@ int setup_profiling_timer(unsigned int multiplier)
 }
 
 /*
- * Setup extended LVT, AMD specific (K8, family 10h)
- *
- * Vector mappings are hard coded. On K8 only offset 0 (APIC500) and
- * MCE interrupts are supported. Thus MCE offset must be set to 0.
- */
-
-#define APIC_EILVT_LVTOFF_MCE 0
-#define APIC_EILVT_LVTOFF_IBS 1
-
-static void setup_APIC_eilvt(u8 lvt_off, u8 vector, u8 msg_type, u8 mask)
-{
-        unsigned long reg = (lvt_off << 4) + APIC_EILVT0;
-        unsigned int  v   = (mask << 16) | (msg_type << 8) | vector;
-        apic_write(reg, v);
-}
-
-u8 setup_APIC_eilvt_mce(u8 vector, u8 msg_type, u8 mask)
-{
-        setup_APIC_eilvt(APIC_EILVT_LVTOFF_MCE, vector, msg_type, mask);
-        return APIC_EILVT_LVTOFF_MCE;
-}
-
-u8 setup_APIC_eilvt_ibs(u8 vector, u8 msg_type, u8 mask)
-{
-        setup_APIC_eilvt(APIC_EILVT_LVTOFF_IBS, vector, msg_type, mask);
-        return APIC_EILVT_LVTOFF_IBS;
-}
-
-/*
  * Local APIC start and shutdown
  */
 
@@ -1542,6 +1546,11 @@ void __cpuinit generic_processor_info(int apicid, int version)
 #ifdef CONFIG_PM
 
 static struct {
+        /*
+         * 'active' is true if the local APIC was enabled by us and
+         * not the BIOS; this signifies that we are also responsible
+         * for disabling it before entering apm/acpi suspend
+         */
         int active;
         /* r/w apic fields */
         unsigned int apic_id;