1 files changed, 32 insertions, 21 deletions

diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
index 3df338481004..c20171078d1d 100644
--- a/drivers/clocksource/acpi_pm.c
+++ b/drivers/clocksource/acpi_pm.c
@@ -21,6 +21,7 @@
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/pci.h>
+#include <linux/delay.h>
 #include <asm/io.h>
 
 /*
@@ -151,13 +152,13 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_LE,
  */
 static int verify_pmtmr_rate(void)
 {
-        u32 value1, value2;
+        cycle_t value1, value2;
         unsigned long count, delta;
 
         mach_prepare_counter();
-        value1 = read_pmtmr();
+        value1 = clocksource_acpi_pm.read();
         mach_countup(&count);
-        value2 = read_pmtmr();
+        value2 = clocksource_acpi_pm.read();
         delta = (value2 - value1) & ACPI_PM_MASK;
 
         /* Check that the PMTMR delta is within 5% of what we expect */
@@ -175,10 +176,15 @@ static int verify_pmtmr_rate(void)
 #define verify_pmtmr_rate() (0)
 #endif
 
+/* Number of monotonicity checks to perform during initialization */
+#define ACPI_PM_MONOTONICITY_CHECKS 10
+/* Number of reads we try to get two different values */
+#define ACPI_PM_READ_CHECKS 10000
+
 static int __init init_acpi_pm_clocksource(void)
 {
-        u32 value1, value2;
-        unsigned int i;
+        cycle_t value1, value2;
+        unsigned int i, j = 0;
 
         if (!pmtmr_ioport)
                 return -ENODEV;
@@ -187,24 +193,29 @@ static int __init init_acpi_pm_clocksource(void)
                                                 clocksource_acpi_pm.shift);
 
         /* "verify" this timing source: */
-        value1 = read_pmtmr();
-        for (i = 0; i < 10000; i++) {
-                value2 = read_pmtmr();
-                if (value2 == value1)
-                        continue;
-                if (value2 > value1)
-                        goto pm_good;
-                if ((value2 < value1) && ((value2) < 0xFFF))
-                        goto pm_good;
-                printk(KERN_INFO "PM-Timer had inconsistent results:"
-                        " 0x%#x, 0x%#x - aborting.\n", value1, value2);
-                return -EINVAL;
+        for (j = 0; j < ACPI_PM_MONOTONICITY_CHECKS; j++) {
+                udelay(100 * j);
+                value1 = clocksource_acpi_pm.read();
+                for (i = 0; i < ACPI_PM_READ_CHECKS; i++) {
+                        value2 = clocksource_acpi_pm.read();
+                        if (value2 == value1)
+                                continue;
+                        if (value2 > value1)
+                                break;
+                        if ((value2 < value1) && ((value2) < 0xFFF))
+                                break;
+                        printk(KERN_INFO "PM-Timer had inconsistent results:"
+                               " 0x%#llx, 0x%#llx - aborting.\n",
+                               value1, value2);
+                        return -EINVAL;
+                }
+                if (i == ACPI_PM_READ_CHECKS) {
+                        printk(KERN_INFO "PM-Timer failed consistency check "
+                               " (0x%#llx) - aborting.\n", value1);
+                        return -ENODEV;
+                }
         }
-        printk(KERN_INFO "PM-Timer had no reasonable result:"
-                        " 0x%#x - aborting.\n", value1);
-        return -ENODEV;
 
-pm_good:
         if (verify_pmtmr_rate() != 0)
                 return -ENODEV;