Merge branch 'upstream'

[pandora-kernel.git] / arch / i386 / kernel / cpu / cpufreq / speedstep-lib.c

diff --git a/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c b/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c
index d368b3f..7c47005 100644 (file)
--- a/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c
+++ b/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c
@@ -320,11 +320,13 @@ EXPORT_SYMBOL_GPL(speedstep_detect_processor);
 unsigned int speedstep_get_freqs(unsigned int processor,
                                  unsigned int *low_speed,
                                  unsigned int *high_speed,
+                                 unsigned int *transition_latency,
                                  void (*set_state) (unsigned int state))
 {
        unsigned int prev_speed;
        unsigned int ret = 0;
        unsigned long flags;
+       struct timeval tv1, tv2;
 
        if ((!processor) || (!low_speed) || (!high_speed) || (!set_state))
                return -EINVAL;
@@ -337,7 +339,7 @@ unsigned int speedstep_get_freqs(unsigned int processor,
                return -EIO;
 
        dprintk("previous speed is %u\n", prev_speed);
-       
+
        local_irq_save(flags);
 
        /* switch to low state */
@@ -350,8 +352,17 @@ unsigned int speedstep_get_freqs(unsigned int processor,
 
        dprintk("low speed is %u\n", *low_speed);
 
+       /* start latency measurement */
+       if (transition_latency)
+               do_gettimeofday(&tv1);
+
        /* switch to high state */
        set_state(SPEEDSTEP_HIGH);
+
+       /* end latency measurement */
+       if (transition_latency)
+               do_gettimeofday(&tv2);
+
        *high_speed = speedstep_get_processor_frequency(processor);
        if (!*high_speed) {
                ret = -EIO;
@@ -369,6 +380,25 @@ unsigned int speedstep_get_freqs(unsigned int processor,
        if (*high_speed != prev_speed)
                set_state(SPEEDSTEP_LOW);
 
+       if (transition_latency) {
+               *transition_latency = (tv2.tv_sec - tv1.tv_sec) * USEC_PER_SEC +
+                       tv2.tv_usec - tv1.tv_usec;
+               dprintk("transition latency is %u uSec\n", *transition_latency);
+
+               /* convert uSec to nSec and add 20% for safety reasons */
+               *transition_latency *= 1200;
+
+               /* check if the latency measurement is too high or too low
+                * and set it to a safe value (500uSec) in that case
+                */
+               if (*transition_latency > 10000000 || *transition_latency < 50000) {
+                       printk (KERN_WARNING "speedstep: frequency transition measured seems out of "
+                                       "range (%u nSec), falling back to a safe one of %u nSec.\n",
+                                       *transition_latency, 500000);
+                       *transition_latency = 500000;
+               }
+       }
+
  out:
        local_irq_restore(flags);
        return (ret);