1 files changed, 65 insertions, 52 deletions

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 2383bcf18c5d..93aa911646ad 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -28,6 +28,7 @@
 #include <linux/clockchips.h>
 #include <linux/acpi_pmtmr.h>
 #include <linux/module.h>
+#include <linux/dmi.h>
 
 #include <asm/atomic.h>
 #include <asm/smp.h>
@@ -61,6 +62,11 @@ static int enable_local_apic __initdata = 0;
 
 /* Local APIC timer verification ok */
 static int local_apic_timer_verify_ok;
+/* Disable local APIC timer from the kernel commandline or via dmi quirk */
+static int local_apic_timer_disabled;
+/* Local APIC timer works in C2 */
+int local_apic_timer_c2_ok;
+EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
 
 /*
  * Debug level, exported for io_apic.c
@@ -338,6 +344,23 @@ void __init setup_boot_APIC_clock(void)
         void (*real_handler)(struct clock_event_device *dev);
         unsigned long deltaj;
         long delta, deltapm;
+        int pm_referenced = 0;
+
+        if (boot_cpu_has(X86_FEATURE_LAPIC_TIMER_BROKEN))
+                local_apic_timer_disabled = 1;
+
+        /*
+         * The local apic timer can be disabled via the kernel
+         * commandline or from the test above. Register the lapic
+         * timer as a dummy clock event source on SMP systems, so the
+         * broadcast mechanism is used. On UP systems simply ignore it.
+         */
+        if (local_apic_timer_disabled) {
+                /* No broadcast on UP ! */
+                if (num_possible_cpus() > 1)
+                        setup_APIC_timer();
+                return;
+        }
 
         apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n"
                     "calibrating APIC timer ...\n");
@@ -357,7 +380,8 @@ void __init setup_boot_APIC_clock(void)
         /* Let the interrupts run */
         local_irq_enable();
 
-        while(lapic_cal_loops <= LAPIC_CAL_LOOPS);
+        while (lapic_cal_loops <= LAPIC_CAL_LOOPS)
+                cpu_relax();
 
         local_irq_disable();
 
@@ -394,6 +418,7 @@ void __init setup_boot_APIC_clock(void)
                                "%lu (%ld)\n", (unsigned long) res, delta);
                         delta = (long) res;
                 }
+                pm_referenced = 1;
         }
 
         /* Calculate the scaled math multiplication factor */
@@ -423,69 +448,43 @@ void __init setup_boot_APIC_clock(void)
                     calibration_result / (1000000 / HZ),
                     calibration_result % (1000000 / HZ));
 
-
-        apic_printk(APIC_VERBOSE, "... verify APIC timer\n");
-
-        /*
-         * Setup the apic timer manually
-         */
         local_apic_timer_verify_ok = 1;
-        levt->event_handler = lapic_cal_handler;
-        lapic_timer_setup(CLOCK_EVT_MODE_PERIODIC, levt);
-        lapic_cal_loops = -1;
 
-        /* Let the interrupts run */
-        local_irq_enable();
+        /* We trust the pm timer based calibration */
+        if (!pm_referenced) {
+                apic_printk(APIC_VERBOSE, "... verify APIC timer\n");
 
-        while(lapic_cal_loops <= LAPIC_CAL_LOOPS);
+                /*
+                 * Setup the apic timer manually
+                 */
+                levt->event_handler = lapic_cal_handler;
+                lapic_timer_setup(CLOCK_EVT_MODE_PERIODIC, levt);
+                lapic_cal_loops = -1;
 
-        local_irq_disable();
+                /* Let the interrupts run */
+                local_irq_enable();
 
-        /* Stop the lapic timer */
-        lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, levt);
+                while(lapic_cal_loops <= LAPIC_CAL_LOOPS)
+                        cpu_relax();
 
-        local_irq_enable();
+                local_irq_disable();
 
-        /* Jiffies delta */
-        deltaj = lapic_cal_j2 - lapic_cal_j1;
-        apic_printk(APIC_VERBOSE, "... jiffies delta = %lu\n", deltaj);
+                /* Stop the lapic timer */
+                lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, levt);
 
-        /* Check, if the PM timer is available */
-        deltapm = lapic_cal_pm2 - lapic_cal_pm1;
-        apic_printk(APIC_VERBOSE, "... PM timer delta = %ld\n", deltapm);
+                local_irq_enable();
 
-        local_apic_timer_verify_ok = 0;
+                /* Jiffies delta */
+                deltaj = lapic_cal_j2 - lapic_cal_j1;
+                apic_printk(APIC_VERBOSE, "... jiffies delta = %lu\n", deltaj);
 
-        if (deltapm) {
-                if (deltapm > (pm_100ms - pm_thresh) &&
-                    deltapm < (pm_100ms + pm_thresh)) {
-                        apic_printk(APIC_VERBOSE, "... PM timer result ok\n");
-                        /* Check, if the jiffies result is consistent */
-                        if (deltaj < LAPIC_CAL_LOOPS-2 ||
-                            deltaj > LAPIC_CAL_LOOPS+2) {
-                                /*
-                                 * Not sure, what we can do about this one.
-                                 * When high resultion timers are active
-                                 * and the lapic timer does not stop in C3
-                                 * we are fine. Otherwise more trouble might
-                                 * be waiting. -- tglx
-                                 */
-                                printk(KERN_WARNING "Global event device %s "
-                                       "has wrong frequency "
-                                       "(%lu ticks instead of %d)\n",
-                                       global_clock_event->name, deltaj,
-                                       LAPIC_CAL_LOOPS);
-                        }
-                        local_apic_timer_verify_ok = 1;
-                }
-        } else {
                 /* Check, if the jiffies result is consistent */
-                if (deltaj >= LAPIC_CAL_LOOPS-2 &&
-                    deltaj <= LAPIC_CAL_LOOPS+2) {
+                if (deltaj >= LAPIC_CAL_LOOPS-2 && deltaj <= LAPIC_CAL_LOOPS+2)
                         apic_printk(APIC_VERBOSE, "... jiffies result ok\n");
-                        local_apic_timer_verify_ok = 1;
-                }
-        }
+                else
+                        local_apic_timer_verify_ok = 0;
+        } else
+                local_irq_enable();
 
         if (!local_apic_timer_verify_ok) {
                 printk(KERN_WARNING
@@ -1203,6 +1202,20 @@ static int __init parse_nolapic(char *arg)
 }
 early_param("nolapic", parse_nolapic);
 
+static int __init parse_disable_lapic_timer(char *arg)
+{
+        local_apic_timer_disabled = 1;
+        return 0;
+}
+early_param("nolapic_timer", parse_disable_lapic_timer);
+
+static int __init parse_lapic_timer_c2_ok(char *arg)
+{
+        local_apic_timer_c2_ok = 1;
+        return 0;
+}
+early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok);
+
 static int __init apic_set_verbosity(char *str)
 {
         if (strcmp("debug", str) == 0)