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Subject[PATCH 1/2] acpi_pm.c: use proper read function also in errata mode.
On all hardware (some Intel ICH4, PIIX4 and PIIX4E chipsets) affected by a
hardware errata there's about a 4.2% chance that initialization of the ACPI
PMTMR fails. On those chipsets, we need to read out the timer value at least
three times to get a correct result, for every once in a while (i.e. within
a 3 ns window every 69.8 ns) the read returns a bogus result. During normal
operation we work around this issue, but during initialization reading a
bogus value may lead to -EINVAL even though the hardware is usable.

Thanks to Andreas Mohr for spotting this issue.

CC: John Stultz <johnstul@us.ibm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
drivers/clocksource/acpi_pm.c | 16 ++++++++--------
1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
index 5ca1d80..2c00edd 100644
--- a/drivers/clocksource/acpi_pm.c
+++ b/drivers/clocksource/acpi_pm.c
@@ -151,13 +151,13 @@ 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 */
@@ -177,7 +177,7 @@ static int verify_pmtmr_rate(void)

static int __init init_acpi_pm_clocksource(void)
{
- u32 value1, value2;
+ cycle_t value1, value2;
unsigned int i;

if (!pmtmr_ioport)
@@ -187,9 +187,9 @@ static int __init init_acpi_pm_clocksource(void)
clocksource_acpi_pm.shift);

/* "verify" this timing source: */
- value1 = read_pmtmr();
+ value1 = clocksource_acpi_pm.read();
for (i = 0; i < 10000; i++) {
- value2 = read_pmtmr();
+ value2 = clocksource_acpi_pm.read();
if (value2 == value1)
continue;
if (value2 > value1)
@@ -197,11 +197,11 @@ static int __init init_acpi_pm_clocksource(void)
if ((value2 < value1) && ((value2) < 0xFFF))
goto pm_good;
printk(KERN_INFO "PM-Timer had inconsistent results:"
- " 0x%#x, 0x%#x - aborting.\n", value1, value2);
+ " 0x%#llx, 0x%#llx - aborting.\n", value1, value2);
return -EINVAL;
}
printk(KERN_INFO "PM-Timer had no reasonable result:"
- " 0x%#x - aborting.\n", value1);
+ " 0x%#llx - aborting.\n", value1);
return -ENODEV;

pm_good:

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