From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + acpi_pmc-check-for-monotonicity.patch added to -mm tree Date: Mon, 18 Aug 2008 13:21:02 -0700 Message-ID: <200808182021.m7IKL2Be010575@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:37641 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752648AbYHRUWW (ORCPT ); Mon, 18 Aug 2008 16:22:22 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: linux@dominikbrodowski.net, andi@firstfloor.org, andi@lisas.de, johnstul@us.ibm.com, mingo@elte.hu, tglx@linutronix.de The patch titled acpi_pm.c: check for monotonicity has been added to the -mm tree. Its filename is acpi_pmc-check-for-monotonicity.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: acpi_pm.c: check for monotonicity From: Dominik Brodowski The current check for monotonicity is way too weak: Andreas Mohr reports ( http://lkml.org/lkml/2008/8/10/77 ) that on one of his test systems the current check only triggers in 50% of all cases, leading to catastrophic timer behaviour. To fix this issue, expand the check for monotonicity by doing ten consecutive tests instead of one. Cc: John Stultz Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Dominik Brodowski Cc: Andreas Mohr Cc: Andi Kleen Signed-off-by: Andrew Morton --- drivers/clocksource/acpi_pm.c | 42 +++++++++++++++++++------------- 1 file changed, 25 insertions(+), 17 deletions(-) diff -puN drivers/clocksource/acpi_pm.c~acpi_pmc-check-for-monotonicity drivers/clocksource/acpi_pm.c --- a/drivers/clocksource/acpi_pm.c~acpi_pmc-check-for-monotonicity +++ a/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_clocksour 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; _ Patches currently in -mm which might be from linux@dominikbrodowski.net are linux-next.patch pcmcia-pccard-deadlock-fix.patch acpi_pmc-use-proper-read-function-also-in-errata-mode.patch acpi_pmc-check-for-monotonicity.patch make-sure-nobodys-leaking-resources.patch