Messages in this thread Patch in this message | | | Date | Sun, 10 Aug 2008 22:02:24 +0200 | From | Dominik Brodowski <> | Subject | Re: ACPI PM-Timer on K6-3 SiS5591: Houston... |
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Hi Andreas,
On Sun, Aug 10, 2008 at 09:08:02PM +0200, Andreas Mohr wrote: > And it's in fact not this triple-read which has any weakness here but rather > the init check.
right.
> IMHO the current init check is too weak, it will catch the very simplest > types of problems only, and that's not a good thing.
what about this?
Best, Dominik
acpi_pm.c: check for monotonicity
Expand the check for monotonicity by doing ten tests instead of one.
Applies on top of "acpi_pm.c: use proper read function also in errata mode."
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.de>
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c index 2c00edd..f05c4fb 100644 --- a/drivers/clocksource/acpi_pm.c +++ b/drivers/clocksource/acpi_pm.c @@ -178,7 +178,7 @@ static int verify_pmtmr_rate(void) static int __init init_acpi_pm_clocksource(void) { cycle_t value1, value2; - unsigned int i; + unsigned int i, j, good = 0; if (!pmtmr_ioport) return -ENODEV; @@ -187,24 +187,32 @@ static int __init init_acpi_pm_clocksource(void) clocksource_acpi_pm.shift); /* "verify" this timing source: */ - value1 = clocksource_acpi_pm.read(); - for (i = 0; i < 10000; i++) { - value2 = clocksource_acpi_pm.read(); - if (value2 == value1) - continue; - if (value2 > value1) - goto pm_good; - if ((value2 < value1) && ((value2) < 0xFFF)) - goto pm_good; - printk(KERN_INFO "PM-Timer had inconsistent results:" - " 0x%#llx, 0x%#llx - aborting.\n", value1, value2); - return -EINVAL; + for (j = 0; j < 10; j++) { + value1 = clocksource_acpi_pm.read(); + for (i = 0; i < 10000; i++) { + value2 = clocksource_acpi_pm.read(); + if (value2 == value1) + continue; + if (value2 > value1) + good++; + break; + if ((value2 < value1) && ((value2) < 0xFFF)) + good++; + break; + printk(KERN_INFO "PM-Timer had inconsistent results:" + " 0x%#llx, 0x%#llx - aborting.\n", + value1, value2); + return -EINVAL; + } + udelay(300 * i); + } + + if (good != 10) { + printk(KERN_INFO "PM-Timer had no reasonable result:" + " 0x%#llx - aborting.\n", value1); + return -ENODEV; } - printk(KERN_INFO "PM-Timer had no reasonable result:" - " 0x%#llx - aborting.\n", value1); - return -ENODEV; -pm_good: if (verify_pmtmr_rate() != 0) return -ENODEV;
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