diff --git a/conf.c b/conf.c
index 54652a0..bce06fa 100644
--- a/conf.c
+++ b/conf.c
@@ -1430,8 +1430,8 @@ static void
 parse_hwtimestamp(char *line)
 {
   CNF_HwTsInterface *iface;
+  int n, maxpoll_set = 0;
   char *p, filter[5];
-  int n;
 
   if (!*line) {
     command_parse_error();
@@ -1461,6 +1461,10 @@ parse_hwtimestamp(char *line)
     } else if (!strcasecmp(p, "minpoll")) {
       if (sscanf(line, "%d%n", &iface->minpoll, &n) != 1)
         break;
+    } else if (!strcasecmp(p, "maxpoll")) {
+      if (sscanf(line, "%d%n", &iface->maxpoll, &n) != 1)
+        break;
+      maxpoll_set = 1;
     } else if (!strcasecmp(p, "minsamples")) {
       if (sscanf(line, "%d%n", &iface->min_samples, &n) != 1)
         break;
@@ -1496,6 +1500,9 @@ parse_hwtimestamp(char *line)
 
   if (*p)
     command_parse_error();
+
+  if (!maxpoll_set)
+    iface->maxpoll = iface->minpoll + 1;
 }
 
 /* ================================================== */
diff --git a/conf.h b/conf.h
index 5ce6559..ca18abc 100644
--- a/conf.h
+++ b/conf.h
@@ -144,6 +144,7 @@ typedef enum {
 typedef struct {
   char *name;
   int minpoll;
+  int maxpoll;
   int min_samples;
   int max_samples;
   int nocrossts;
diff --git a/doc/chrony.conf.adoc b/doc/chrony.conf.adoc
index 02e3bfa..49d5168 100644
--- a/doc/chrony.conf.adoc
+++ b/doc/chrony.conf.adoc
@@ -2549,10 +2549,15 @@ The *hwtimestamp* directive has the following options:
 +
 *minpoll* _poll_:::
 This option specifies the minimum interval between readings of the NIC clock.
-It's defined as a power of two. It should correspond to the minimum polling
+It's defined as a power of 2. It should correspond to the minimum polling
 interval of all NTP sources and the minimum expected polling interval of NTP
-clients. The default value is 0 (1 second) and the minimum value is -6 (1/64th
-of a second).
+clients. The default value is 0 (1 second), the minimum value is -6 (1/64th
+of a second), and the maximum value is 20 (about 12 days).
+*maxpoll* _poll_:::
+This option specifies the maximum interval between readings of the NIC clock,
+as a power of 2. The default value is *minpoll* + 1, i.e. 1 (2 seconds) with
+the default *minpoll* of 0. The minimum and maximum values are the same as with
+the *minpoll* option.
 *minsamples* _samples_:::
 This option specifies the minimum number of readings kept for tracking of the
 NIC clock. The default value is 2.
diff --git a/ntp_io_linux.c b/ntp_io_linux.c
index 3f0620a..41d581b 100644
--- a/ntp_io_linux.c
+++ b/ntp_io_linux.c
@@ -64,13 +64,16 @@ struct Interface {
   double tx_comp;
   double rx_comp;
   HCL_Instance clock;
+  int maxpoll;
+  SCH_TimeoutID poll_timeout_id;
 };
 
 /* Number of PHC readings per HW clock sample */
 #define PHC_READINGS 25
 
-/* Minimum interval between PHC readings */
+/* Minimum and maximum interval between PHC readings */
 #define MIN_PHC_POLL -6
+#define MAX_PHC_POLL 20
 
 /* Maximum acceptable offset between SW/HW and daemon timestamp */
 #define MAX_TS_DELAY 1.0
@@ -110,13 +113,17 @@ static int dummy_rxts_socket;
 
 /* ================================================== */
 
+static void poll_phc(struct Interface *iface, struct timespec *now);
+
+/* ================================================== */
+
 static int
 add_interface(CNF_HwTsInterface *conf_iface)
 {
+  int sock_fd, if_index, minpoll, phc_fd, req_hwts_flags, rx_filter;
   struct ethtool_ts_info ts_info;
   struct hwtstamp_config ts_config;
   struct ifreq req;
-  int sock_fd, if_index, phc_fd, req_hwts_flags, rx_filter;
   unsigned int i;
   struct Interface *iface;
 
@@ -248,9 +255,15 @@ add_interface(CNF_HwTsInterface *conf_iface)
   iface->tx_comp = conf_iface->tx_comp;
   iface->rx_comp = conf_iface->rx_comp;
 
+  minpoll = CLAMP(MIN_PHC_POLL, conf_iface->minpoll, MAX_PHC_POLL);
   iface->clock = HCL_CreateInstance(conf_iface->min_samples, conf_iface->max_samples,
-                                    UTI_Log2ToDouble(MAX(conf_iface->minpoll, MIN_PHC_POLL)),
-                                    conf_iface->precision);
+                                    UTI_Log2ToDouble(minpoll), conf_iface->precision);
+
+  iface->maxpoll = CLAMP(minpoll, conf_iface->maxpoll, MAX_PHC_POLL);
+
+  /* Do not schedule the first poll timeout here!  The argument (interface) can
+     move until all interfaces are added.  Wait for the first HW timestamp. */
+  iface->poll_timeout_id = 0;
 
   LOG(LOGS_INFO, "Enabled HW timestamping %son %s",
       ts_config.rx_filter == HWTSTAMP_FILTER_NONE ? "(TX only) " : "", iface->name);
@@ -436,6 +449,7 @@ NIO_Linux_Finalise(void)
 
   for (i = 0; i < ARR_GetSize(interfaces); i++) {
     iface = ARR_GetElement(interfaces, i);
+    SCH_RemoveTimeout(iface->poll_timeout_id);
     HCL_DestroyInstance(iface->clock);
     close(iface->phc_fd);
   }
@@ -580,29 +594,70 @@ get_interface(int if_index)
 
 /* ================================================== */
 
+static void
+poll_timeout(void *arg)
+{
+  struct Interface *iface = arg;
+  struct timespec now;
+
+  iface->poll_timeout_id = 0;
+
+  SCH_GetLastEventTime(&now, NULL, NULL);
+  poll_phc(iface, &now);
+}
+
+/* ================================================== */
+
+static void
+poll_phc(struct Interface *iface, struct timespec *now)
+{
+  struct timespec sample_phc_ts, sample_sys_ts, sample_local_ts;
+  struct timespec phc_readings[PHC_READINGS][3];
+  double phc_err, local_err, interval;
+  int n_readings;
+
+  if (!HCL_NeedsNewSample(iface->clock, now))
+    return;
+
+  DEBUG_LOG("Polling PHC on %s%s",
+            iface->name, iface->poll_timeout_id != 0 ? " before timeout" : "");
+
+  n_readings = SYS_Linux_GetPHCReadings(iface->phc_fd, iface->phc_nocrossts,
+                                        &iface->phc_mode, PHC_READINGS, phc_readings);
+
+  /* Add timeout for the next poll in case no HW timestamp will be captured
+     between the minpoll and maxpoll.  Separate reading of different PHCs to
+     avoid long intervals between handling I/O events. */
+  SCH_RemoveTimeout(iface->poll_timeout_id);
+  interval = UTI_Log2ToDouble(iface->maxpoll);
+  iface->poll_timeout_id = SCH_AddTimeoutInClass(interval, interval /
+                                                   ARR_GetSize(interfaces) / 4, 0.1,
+                                                 SCH_PhcPollClass, poll_timeout, iface);
+
+  if (n_readings <= 0)
+    return;
+
+  if (!HCL_ProcessReadings(iface->clock, n_readings, phc_readings,
+                           &sample_phc_ts, &sample_sys_ts, &phc_err))
+    return;
+
+  LCL_CookTime(&sample_sys_ts, &sample_local_ts, &local_err);
+  HCL_AccumulateSample(iface->clock, &sample_phc_ts, &sample_local_ts, phc_err + local_err);
+
+  update_interface_speed(iface);
+}
+
+/* ================================================== */
+
 static void
 process_hw_timestamp(struct Interface *iface, struct timespec *hw_ts,
                      NTP_Local_Timestamp *local_ts, int rx_ntp_length, int family,
                      int l2_length)
 {
-  struct timespec sample_phc_ts, sample_sys_ts, sample_local_ts, ts;
-  struct timespec phc_readings[PHC_READINGS][3];
-  double rx_correction, ts_delay, phc_err, local_err;
-  int n_readings;
+  double rx_correction, ts_delay, local_err;
+  struct timespec ts;
 
-  if (HCL_NeedsNewSample(iface->clock, &local_ts->ts)) {
-    n_readings = SYS_Linux_GetPHCReadings(iface->phc_fd, iface->phc_nocrossts,
-                                          &iface->phc_mode, PHC_READINGS, phc_readings);
-    if (n_readings > 0 &&
-        HCL_ProcessReadings(iface->clock, n_readings, phc_readings,
-                             &sample_phc_ts, &sample_sys_ts, &phc_err)) {
-      LCL_CookTime(&sample_sys_ts, &sample_local_ts, &local_err);
-      HCL_AccumulateSample(iface->clock, &sample_phc_ts, &sample_local_ts,
-                           phc_err + local_err);
-
-      update_interface_speed(iface);
-    }
-  }
+  poll_phc(iface, &local_ts->ts);
 
   /* We need to transpose RX timestamps as hardware timestamps are normally
      preamble timestamps and RX timestamps in NTP are supposed to be trailer
diff --git a/sched.h b/sched.h
index f1f4eb9..90d757f 100644
--- a/sched.h
+++ b/sched.h
@@ -37,6 +37,7 @@ typedef enum {
   SCH_NtpClientClass,
   SCH_NtpPeerClass,
   SCH_NtpBroadcastClass,
+  SCH_PhcPollClass,
   SCH_NumberOfClasses /* needs to be last */
 } SCH_TimeoutClass;
 
diff --git a/test/simulation/133-hwtimestamp b/test/simulation/133-hwtimestamp
index d3cce6d..f02a010 100755
--- a/test/simulation/133-hwtimestamp
+++ b/test/simulation/133-hwtimestamp
@@ -47,9 +47,10 @@ for client_conf in \
 		check_log_messages "Received error.*message.*tss=KH" 195 200 || test_fail
 		check_log_messages "Updated RX timestamp.*tss=1" 1 1 || test_fail
 		check_log_messages "Updated RX timestamp.*tss=2" 195 200 || test_fail
+		check_log_messages "Polling PHC" 195 220 || test_fail
 		if echo "$client_conf" | grep -q nocrossts; then
 			check_log_messages "update_tx_timestamp.*Updated" 180 200 || test_fail
-			check_log_messages "update_tx_timestamp.*Unacceptable" 0 10 || test_fail
+			check_log_messages "update_tx_timestamp.*Unacceptable" 0 13 || test_fail
 		else
 			check_log_messages "update_tx_timestamp.*Updated" 50 140 || test_fail
 			check_log_messages "update_tx_timestamp.*Unacceptable" 50 140 || test_fail
@@ -57,4 +58,32 @@ for client_conf in \
 	fi
 done
 
+server_conf+="
+server 192.168.123.2 minpoll 1 maxpoll 1 noselect"
+
+for maxpoll in -1 0 1; do
+	client_conf="hwtimestamp eth0 minpoll -1 maxpoll $maxpoll nocrossts"
+	run_test || test_fail
+	check_chronyd_exit || test_fail
+	check_source_selection || test_fail
+	check_sync || test_fail
+
+	if check_config_h 'FEAT_DEBUG 1'; then
+		case $maxpoll in
+			-1)
+				check_log_messages "Polling PHC on eth0$" 360 380 || test_fail
+				check_log_messages "Polling PHC.*before" 3 25 || test_fail
+				;;
+			0)
+				check_log_messages "Polling PHC on eth0$" 8 45 || test_fail
+				check_log_messages "Polling PHC.*before" 150 190 || test_fail
+				;;
+			1)
+				check_log_messages "Polling PHC on eth0$" 1 1 || test_fail
+				check_log_messages "Polling PHC.*before" 194 199 || test_fail
+				;;
+		esac
+	fi
+done
+
 test_pass