The patch titled
PM-Timer: doesn't use workaround if chipset is not buggy
has been removed from the -mm tree. Its filename is
time-i386-clocksource-drivers-pm-timer-doesnt-use-workaround-if-chipset-is-not-buggy.patch
This patch was dropped because it was folded into time-i386-clocksource-drivers.patch
------------------------------------------------------
Subject: PM-Timer: doesn't use workaround if chipset is not buggy
From: john stultz <johnstul@xxxxxxxxxx>
My reimplementation of pmtimer workaround from OGAWA Hirofumi.
Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/clocksource/acpi_pm.c | 102 +++++++++++++++++++++++++++++++-
1 file changed, 99 insertions(+), 3 deletions(-)
diff -puN drivers/clocksource/acpi_pm.c~time-i386-clocksource-drivers-pm-timer-doesnt-use-workaround-if-chipset-is-not-buggy drivers/clocksource/acpi_pm.c
--- a/drivers/clocksource/acpi_pm.c~time-i386-clocksource-drivers-pm-timer-doesnt-use-workaround-if-chipset-is-not-buggy
+++ a/drivers/clocksource/acpi_pm.c
@@ -19,6 +19,7 @@
#include <linux/clocksource.h>
#include <linux/errno.h>
#include <linux/init.h>
+#include <linux/pci.h>
#include <asm/io.h>
/* Number of PMTMR ticks expected during calibration run */
@@ -30,6 +31,7 @@
* in arch/i386/acpi/boot.c
*/
u32 pmtmr_ioport;
+static int pmtmr_need_workaround = 1;
#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
@@ -39,6 +41,26 @@ static inline u32 read_pmtmr(void)
return inl(pmtmr_ioport) & ACPI_PM_MASK;
}
+static cycle_t acpi_pm_read_verified(void)
+{
+ u32 v1 = 0, v2 = 0, v3 = 0;
+
+ /*
+ * It has been reported that because of various broken
+ * chipsets (ICH4, PIIX4 and PIIX4E) where the ACPI PM clock
+ * source is not latched, so you must read it multiple
+ * times to ensure a safe value is read:
+ */
+ do {
+ v1 = read_pmtmr();
+ v2 = read_pmtmr();
+ v3 = read_pmtmr();
+ } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
+ || (v3 > v1 && v3 < v2));
+
+ return (cycle_t)v2;
+}
+
static cycle_t acpi_pm_read(void)
{
return (cycle_t)read_pmtmr();
@@ -54,6 +76,73 @@ static struct clocksource clocksource_ac
.is_continuous = 1,
};
+
+#ifdef CONFIG_PCI
+/*
+ * PIIX4 Errata:
+ *
+ * The power management timer may return improper results when read.
+ * Although the timer value settles properly after incrementing,
+ * while incrementing there is a 3 ns window every 69.8 ns where the
+ * timer value is indeterminate (a 4.2% chance that the data will be
+ * incorrect when read). As a result, the ACPI free running count up
+ * timer specification is violated due to erroneous reads.
+ */
+static void __init pmtmr_bug_check(void)
+{
+ static struct pci_device_id gray_list[] __initdata = {
+ /* these chipsets may have bug. */
+ { PCI_DEVICE(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82801DB_0) },
+ { },
+ };
+ struct pci_dev *dev;
+ int pmtmr_has_bug = 0;
+ u8 rev;
+
+ if (!pmtmr_need_workaround)
+ return;
+
+ dev = pci_get_device(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82371AB_3, NULL);
+ if (dev) {
+ pci_read_config_byte(dev, PCI_REVISION_ID, &rev);
+ /* the bug has been fixed in PIIX4M */
+ if (rev < 3) {
+ printk(KERN_WARNING "* Found PM-Timer Bug on this"
+ " chipset. Due to workarounds for a bug,\n"
+ "* this time source is slow. Consider trying"
+ " other time sources (clock=)\n");
+ pmtmr_has_bug = 1;
+ }
+ pci_dev_put(dev);
+ }
+
+ if (pci_dev_present(gray_list)) {
+ printk(KERN_WARNING "* This chipset may have PM-Timer Bug."
+ " Due to workarounds for a bug,\n"
+ "* this time source is slow. If you are sure your"
+ " timer does not have\n"
+ "* this bug, please use \"pmtmr_good\" to disable?"
+ " the workaround\n");
+ pmtmr_has_bug = 1;
+ }
+
+ if (!pmtmr_has_bug)
+ pmtmr_need_workaround = 0;
+}
+#else
+#define pmtmr_bug_check()
+#endif
+
+static int __init pmtr_good_setup(char *__str)
+{
+ pmtmr_need_workaround = 0;
+ return 1;
+}
+__setup("pmtmr_good", pmtr_good_setup);
+
+
static int __init init_acpi_pm_clocksource(void)
{
u32 value1, value2;
@@ -75,14 +164,21 @@ static int __init init_acpi_pm_clocksour
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);
+ printk(KERN_INFO "PM-Timer had inconsistent results:"
+ " 0x%#x, 0x%#x - aborting.\n", value1, value2);
return -EINVAL;
}
- printk(KERN_INFO "PM-Timer had no reasonable result: 0x%#x - aborting.\n", value1);
+ printk(KERN_INFO "PM-Timer had no reasonable result:"
+ " 0x%#x - aborting.\n", value1);
return -ENODEV;
pm_good:
-
+ pmtmr_bug_check();
+ /* check to see if pmtmr is known buggy: */
+ if (pmtmr_need_workaround) {
+ clocksource_acpi_pm.read = acpi_pm_read_verified;
+ clocksource_acpi_pm.rating = 110;
+ }
return register_clocksource(&clocksource_acpi_pm);
}
_
Patches currently in -mm which might be from johnstul@xxxxxxxxxx are
time-clocksource-infrastructure.patch
time-use-clocksource-infrastructure-for-update_wall_time.patch
time-let-user-request-precision-from-current_tick_length.patch
time-use-clocksource-abstraction-for-ntp-adjustments.patch
time-introduce-arch-generic-time-accessors.patch
hangcheck-remove-monotomic_clock-on-x86.patch
time-i386-conversion-part-1-move-timer_pitc-to-i8253c.patch
time-i386-conversion-part-2-rework-tsc-support.patch
time-i386-conversion-part-3-enable-generic-timekeeping.patch
time-i386-conversion-part-4-remove-old-timer_opts-code.patch
time-i386-clocksource-drivers.patch
time-i386-clocksource-drivers-pm-timer-doesnt-use-workaround-if-chipset-is-not-buggy.patch
time-i386-clocksource-drivers-pm-timer-doesnt-use-workaround-if-chipset-is-not-buggy-acpi_pm-cleanup.patch
time-i386-clocksource-drivers-pm-timer-doesnt-use-workaround-if-chipset-is-not-buggy-acpi_pm-cleanup-fix-missing-to-rename-pmtmr_good-to-acpi_pm_good.patch
time-i386-clocksource-drivers-fix-spelling-typos.patch
time-rename-clocksource-functions.patch
make-pmtmr_ioport-__read_mostly.patch
generic-time-add-macro-to-simplify-hide-mask.patch
time-fix-time-going-backward-w-clock=pit.patch
fix-and-optimize-clock-source-update.patch
gtod-add-scx200-hrt-clocksourcediff.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
