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-rw-r--r--kernel/time/clocksource.c18
1 files changed, 17 insertions, 1 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 80189f6f1c5..18b9f5da4ee 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -30,6 +30,7 @@
#include <linux/module.h>
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
#include <linux/tick.h>
+#include <linux/hrtimer.h>
void timecounter_init(struct timecounter *tc,
const struct cyclecounter *cc,
@@ -509,6 +510,18 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
}
}
+ /*
+ * Check to make sure we don't switch to a non-HRT usable
+ * clocksource if HRT is enabled and running
+ */
+ if (hrtimer_hres_active() &&
+ !(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) {
+ printk(KERN_WARNING "%s clocksource is not HRT compatible. "
+ "Cannot switch while in HRT mode\n", ovr->name);
+ ovr = NULL;
+ override_name[0] = 0;
+ }
+
/* Reselect, when the override name has changed */
if (ovr != clocksource_override) {
clocksource_override = ovr;
@@ -537,7 +550,10 @@ sysfs_show_available_clocksources(struct sys_device *dev,
spin_lock_irq(&clocksource_lock);
list_for_each_entry(src, &clocksource_list, list) {
- count += snprintf(buf + count,
+ /* Don't show non-HRES clocksource if HRES is enabled */
+ if (!hrtimer_hres_active() ||
+ (src->flags & CLOCK_SOURCE_VALID_FOR_HRES))
+ count += snprintf(buf + count,
max((ssize_t)PAGE_SIZE - count, (ssize_t)0),
"%s ", src->name);
}