patch-2_6_7-vs1_9_1_12

[linux-2.6.git] / arch / i386 / kernel / timers / timer_tsc.c

diff --git a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
index 907d2ef..b20fe4d 100644 (file)
--- a/arch/i386/kernel/timers/timer_tsc.c
+++ b/arch/i386/kernel/timers/timer_tsc.c
@@ -27,6 +27,8 @@ static unsigned long hpet_last;
 struct timer_opts timer_tsc;
 #endif
 
+static inline void cpufreq_delayed_get(void);
+
 int tsc_disable __initdata = 0;
 
 extern spinlock_t i8253_lock;
@@ -241,6 +243,9 @@ static void mark_offset_tsc(void)
 
                        clock_fallback();
                }
+               /* ... but give the TSC a fair chance */
+               if (lost_count > 25)
+                       cpufreq_delayed_get();
        } else
                lost_count = 0;
        /* update the monotonic base value */
@@ -324,15 +329,40 @@ static void mark_offset_tsc_hpet(void)
 
 
 #ifdef CONFIG_CPU_FREQ
+#include <linux/workqueue.h>
+
+static unsigned int cpufreq_delayed_issched = 0;
+static unsigned int cpufreq_init = 0;
+static struct work_struct cpufreq_delayed_get_work;
+
+static void handle_cpufreq_delayed_get(void *v)
+{
+       unsigned int cpu;
+       for_each_online_cpu(cpu) {
+               cpufreq_get(cpu);
+       }
+       cpufreq_delayed_issched = 0;
+}
+
+/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries
+ * to verify the CPU frequency the timing core thinks the CPU is running
+ * at is still correct.
+ */
+static inline void cpufreq_delayed_get(void) 
+{
+       if (cpufreq_init && !cpufreq_delayed_issched) {
+               cpufreq_delayed_issched = 1;
+               printk(KERN_DEBUG "Losing some ticks... checking if CPU frequency changed.\n");
+               schedule_work(&cpufreq_delayed_get_work);
+       }
+}
+
 /* If the CPU frequency is scaled, TSC-based delays will need a different
- * loops_per_jiffy value to function properly. An exception to this
- * are modern Intel Pentium 4 processors, where the TSC runs at a constant
- * speed independent of frequency scaling. 
+ * loops_per_jiffy value to function properly.
  */
 
 static unsigned int  ref_freq = 0;
 static unsigned long loops_per_jiffy_ref = 0;
-static unsigned int  variable_tsc = 1;
 
 #ifndef CONFIG_SMP
 static unsigned long fast_gettimeoffset_ref = 0;
@@ -356,14 +386,15 @@ time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
        }
 
        if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
-           (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
-               if (variable_tsc)
+           (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
+           (val == CPUFREQ_RESUMECHANGE)) {
+               if (!(freq->flags & CPUFREQ_CONST_LOOPS))
                        cpu_data[freq->cpu].loops_per_jiffy = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
 #ifndef CONFIG_SMP
                if (cpu_khz)
                        cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
                if (use_tsc) {
-                       if (variable_tsc) {
+                       if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
                                fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_ref, freq->new, ref_freq);
                                set_cyc2ns_scale(cpu_khz/1000);
                        }
@@ -382,14 +413,17 @@ static struct notifier_block time_cpufreq_notifier_block = {
 
 static int __init cpufreq_tsc(void)
 {
-       /* P4 and above CPU TSC freq doesn't change when CPU frequency changes*/
-       if ((boot_cpu_data.x86 >= 15) && (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL))
-               variable_tsc = 0;
-
-       return cpufreq_register_notifier(&time_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
+       int ret;
+       INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get, NULL);
+       ret = cpufreq_register_notifier(&time_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
+       if (!ret)
+               cpufreq_init = 1;
+       return ret;
 }
 core_initcall(cpufreq_tsc);
 
+#else /* CONFIG_CPU_FREQ */
+static inline void cpufreq_delayed_get(void) { return; }
 #endif