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Message-ID: <20080822222233.GA547@isilmar.linta.de>
Date: Sat, 23 Aug 2008 00:22:33 +0200
From: Dominik Brodowski <linux@...inikbrodowski.net>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andreas Mohr <andi@...as.de>, linux-kernel@...r.kernel.org,
linux-acpi@...r.kernel.org, johnstul@...ibm.com,
hirofumi@...l.parknet.co.jp, alan@...rguk.ukuu.org.uk,
arjan@...radead.org
Subject: [PATCH v2 1/2] acpi_pm.c: use proper read function also in errata mode
next try...
From: Dominik Brodowski <linux@...inikbrodowski.net>
Date: Fri, 22 Aug 2008 23:49:21 +0200
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@...ibm.com>
CC: Thomas Gleixner <tglx@...utronix.de>
CC: Ingo Molnar <mingo@...e.hu>
Signed-off-by: Dominik Brodowski <linux@...inikbrodowski.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..860d033 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:
--
1.5.2.5
--
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