From: Dominik Brodowski 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 Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Dominik Brodowski Cc: Andreas Mohr Cc: OGAWA Hirofumi Cc: Alan Cox Cc: Andi Kleen Signed-off-by: Andrew Morton --- drivers/clocksource/acpi_pm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff -puN drivers/clocksource/acpi_pm.c~acpi_pmc-use-proper-read-function-also-in-errata-mode drivers/clocksource/acpi_pm.c --- a/drivers/clocksource/acpi_pm.c~acpi_pmc-use-proper-read-function-also-in-errata-mode +++ a/drivers/clocksource/acpi_pm.c @@ -151,13 +151,13 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SE */ 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_clocksour 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_clocksour 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: _