Powertop on linux 2.6.27-rc7 before and after enabling C1 accounting, CPU is AMD Athlon X2 QL60

USB and WiFi drivers were unloaded, every powertop's hint was executed.
And still only 2 hours with almost everything disabled comparing to 3:11h on Vista while browsing Internet.

--- kernels/linux-2.6.27-rc8/drivers/acpi/processor_idle.c      2008-09-30
00:24:02.000000000 +0200
+++ linux/drivers/acpi/processor_idle.c 2008-10-06 00:24:19.000000000 +0200
@@ -501,7 +501,7 @@
      * ------
      * Invoke the current Cx state to put the processor to sleep.
      */
-       if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
+       if (cx->type >= ACPI_STATE_C1) {
             current_thread_info()->status &= ~TS_POLLING;
             /*
              * TS_POLLING-cleared state must be visible before we
@@ -523,12 +523,17 @@
              * Use the appropriate idle routine, the one that would
              * be used without acpi C-states.
              */
+             
+               t1 = jiffies;
+             
             if (pm_idle_save) {
                     pm_idle_save(); /* enables IRQs */
             } else {
                     acpi_safe_halt();
                     local_irq_enable();
             }
+            
+               t2 = jiffies;

             /*
              * TBD: Can't get time duration while in C1, as resumes
@@ -538,8 +543,7 @@
              * Note: the TSC better not stop in C1, sched_clock() will
              *       skew otherwise.
              */
-               sleep_ticks = 0xFFFFFFFF;
-
+               sleep_ticks = ticks_elapsed(t1, t2);
             break;

     case ACPI_STATE_C2:
@@ -642,12 +646,13 @@
             return;
     }
     cx->usage++;
-       if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
+       if (sleep_ticks > 0)
             cx->time += sleep_ticks;

     next_state = pr->power.state;

#ifdef CONFIG_HOTPLUG_CPU
+
     /* Don't do promotion/demotion */
     if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
         !pr->flags.has_cst && !(acpi_gbl_FADT.flags &
ACPI_FADT_C2_MP_SUPPORTED)) {
@@ -811,8 +816,11 @@
     if (!pr)
             return -EINVAL;

+       /* Newer dual-core CPUs use C1E instead of C2 and C3 and
+        * usually do not have _CST definitions or PBLK entries.
+        * ACPI specification allows for that so return zero here */
     if (!pr->pblk)
-               return -ENODEV;
+               return 0;

     /* if info is obtained from pblk/fadt, type equals state */
     pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
@@ -852,6 +860,11 @@
             pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
             pr->power.states[ACPI_STATE_C1].valid = 1;
             pr->power.states[ACPI_STATE_C1].entry_method =
ACPI_CSTATE_HALT;
+               snprintf(pr->power.states[ACPI_STATE_C1].desc,
ACPI_CX_DESC_LEN, "ACPI HLT");
+               if (!pr->power.states[ACPI_STATE_C1].latency)
+                       pr->power.states[ACPI_STATE_C1].latency = 1;
+               if (!pr->power.states[ACPI_STATE_C1].power)
+                       pr->power.states[ACPI_STATE_C1].power = 1000;
     }
     /* the C0 state only exists as a filler in our array */
     pr->power.states[ACPI_STATE_C0].valid = 1;
@@ -1191,12 +1204,11 @@
     memset(pr->power.states, 0, sizeof(pr->power.states));

     result = acpi_processor_get_power_info_cst(pr);
-       if (result == -ENODEV)
-               result = acpi_processor_get_power_info_fadt(pr);
-
     if (result)
-               return result;
+               result = acpi_processor_get_power_info_fadt(pr);

+       /* No valid _CST and FADT, but C1 must be supported,
+        * so here we go */
     acpi_processor_get_power_info_default(pr);

     pr->power.count = acpi_processor_power_verify(pr);
@@ -1216,13 +1228,13 @@
#endif

     /*
-        * if one state of type C2 or C3 is available, mark this
+        * if one state of type C1(e), C2 or C3 is available, mark this
      * CPU as being "idle manageable"
      */
     for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
             if (pr->power.states[i].valid) {
                     pr->power.count = i;
-                       if (pr->power.states[i].type >= ACPI_STATE_C2)
+                       if (pr->power.states[i].type >= ACPI_STATE_C1)
                             pr->flags.power = 1;
             }
     }
@@ -1455,7 +1467,7 @@
static int acpi_idle_enter_c1(struct cpuidle_device *dev,
                           struct cpuidle_state *state)
{
-       u32 t1, t2;
+       u32 t1, t2, elapsed;
     struct acpi_processor *pr;
     struct acpi_processor_cx *cx = cpuidle_get_statedata(state);

@@ -1482,7 +1494,10 @@

     local_irq_enable();
     cx->usage++;
-
+       elapsed = ticks_elapsed(t1, t2);
+       if (elapsed > 0)
+               cx->time += elapsed;
+    
     return ticks_elapsed_in_us(t1, t2);
}