If TSC stops ticking in C3, disable deep sleep when the user forcefully

select TSC as timecounter hardware.

Tested by:	Fabian Keil (freebsd-listen at fabiankeil dot de)

3 files changed, 9 insertions, 0 deletions

diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index 39d6f230b5b2..0c520711ef73 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -492,6 +492,12 @@ tc_windup(void)
 
 	/* Now is a good time to change timecounters. */
 	if (th->th_counter != timecounter) {
+#ifndef __arm__
+		if ((timecounter->tc_flags & TC_FLAGS_C3STOP) != 0)
+			cpu_disable_deep_sleep++;
+		if ((th->th_counter->tc_flags & TC_FLAGS_C3STOP) != 0)
+			cpu_disable_deep_sleep--;
+#endif
 		th->th_counter = timecounter;
 		th->th_offset_count = ncount;
 		tc_min_ticktock_freq = max(1, timecounter->tc_frequency /
diff --git a/sys/sys/timetc.h b/sys/sys/timetc.h
index dc1dea408c6e..6881b95ed154 100644
--- a/sys/sys/timetc.h
+++ b/sys/sys/timetc.h
@@ -57,6 +57,8 @@ struct timecounter {
 		 * another timecounter higher means better.  Negative
 		 * means "only use at explicit request".
 		 */
+	u_int			tc_flags;
+#define	TC_FLAGS_C3STOP		1	/* Timer dies in C3. */
 
 	void			*tc_priv;
 		/* Pointer to the timecounter's private parts. */
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c
index 5f17f62d923e..0b383bf7ef21 100644
--- a/sys/x86/x86/tsc.c
+++ b/sys/x86/x86/tsc.c
@@ -452,6 +452,7 @@ init_TSC_tc(void)
 	if (cpu_can_deep_sleep && cpu_vendor_id == CPU_VENDOR_INTEL &&
 	    (amd_pminfo & AMDPM_TSC_INVARIANT) == 0) {
 		tsc_timecounter.tc_quality = -1000;
+		tsc_timecounter.tc_flags |= TC_FLAGS_C3STOP;
 		if (bootverbose)
 			printf("TSC timecounter disabled: C3 enabled.\n");
 		goto init;