From: Prarit Bhargava <prarit@redhat.com>
Date: Mon, 15 Dec 2008 15:26:28 -0500
Subject: [x86] consistent time options for x86_64 and i386
Message-id: 4946BD74.8050404@redhat.com
O-Subject: Re: [RHEL 5.4 PATCH]: Consistent time options for x86_64 and i386
Bugzilla: 475374
RH-Acked-by: Brian Maly <bmaly@redhat.com>

x86_64 uses nopmtimer, nohpet, and notsc to control which clock is used for
the GTOD clock.  i386 uses "clock=[hpet|pmtmr|tsc]" to control which clock
is used for both the wall and the GTOD clock.

Make them consistent between arches.

disable_pmtmr() is not upstream -- I have pushed a patch to add it
upstream.

Tested on an xw9400 with HPET enabled and disabled on both i386 & x86_64 by
me.

Resolves BZ 475374.

diff --git a/arch/i386/kernel/time_hpet.c b/arch/i386/kernel/time_hpet.c
index cf206c8..df5eee4 100644
--- a/arch/i386/kernel/time_hpet.c
+++ b/arch/i386/kernel/time_hpet.c
@@ -247,6 +247,13 @@ static int __init hpet_setup(char* str)
 
 __setup("hpet=", hpet_setup);
 
+static int __init disable_hpet(char *str)
+{
+	boot_hpet_disable = 1;
+	return 1;
+}
+__setup("nohpet", disable_hpet);
+
 #ifdef CONFIG_HPET_EMULATE_RTC
 /* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
  * is enabled, we support RTC interrupt functionality in software.
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 82ba6a8..9ad5528 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -1444,6 +1444,25 @@ int __init notsc_setup(char *s)
 
 __setup("notsc", notsc_setup);
 
+static int __init boot_override_clock(char *str)
+{
+	/* For x86, only have hpet, pmtmr, tsc */
+	if (!strcmp(str, "hpet")) {
+		pmtmr_ioport = 0;
+		notsc = 1;
+	} else if (!strcmp(str, "pmtmr") || !strcmp(str, "pmtimer")) {
+		nohpet = 1;
+		notsc = 1;
+	} else if (!strcmp(str, "tsc")) {
+		nohpet = 1;
+		pmtmr_ioport = 0;
+	} else
+		printk(KERN_WARNING "%s is unknown clock source\n", str);
+
+	return 1;
+}
+__setup("clock=", boot_override_clock);
+
 #ifdef CONFIG_TICK_DIVIDER
 
 
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
index 7ad3be8..a770228 100644
--- a/drivers/clocksource/acpi_pm.c
+++ b/drivers/clocksource/acpi_pm.c
@@ -174,4 +174,11 @@ pm_good:
 	return clocksource_register(&clocksource_acpi_pm);
 }
 
+
+static int __init disable_pmtmr(char *str)
+{
+	pmtmr_ioport = 0;
+	return 1;
+}
+__setup("nopmtimer", disable_pmtmr);
 module_init(init_acpi_pm_clocksource);