clocksource, 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. Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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