commit 1a2dfe9b00b79a59acf905476bbc33c74d5770a3
Author: Jacob Keller <jacob.e.keller@intel.com>
Date:   Thu Jul 8 12:59:30 2021 -0700

    Increase the default tx_timestamp_timeout to 10
    
    The tx_timestamp_timeout configuration defines the number of
    milliseconds to wait for a Tx timestamp from the kernel stack. This
    delay is necessary as Tx timestamps are captured after a packet is sent
    and reported back via the socket error queue.
    
    The current default is to poll for up to 1 millisecond. In practice, it
    turns out that this is not always enough time for hardware and software
    to capture the timestamp and report it back. Some hardware designs
    require reading timestamps over registers or other slow mechanisms.
    
    This extra delay results in the timestamp not being sent back to
    userspace within the default 1 millisecond polling time. If that occurs
    the following can be seen from ptp4l:
    
      ptp4l[4756.840]: timed out while polling for tx timestamp
      ptp4l[4756.840]: increasing tx_timestamp_timeout may correct this issue,
                       but it is likely caused by a driver bug
      ptp4l[4756.840]: port 1 (p2p1): send sync failed
      ptp4l[4756.840]: port 1 (p2p1): MASTER to FAULTY on FAULT_DETECTED
                       (FT_UNSPECIFIED)
    
    This can confuse users because it implies this is a bug, when the
    correct solution in many cases is to just increase the timeout to
    a slightly higher value.
    
    Since we know this is a problem for many drivers and hardware designs,
    lets increase the default timeout.
    
    Note that a longer timeout should not affect setups which return the
    timestamp quickly. On modern kernels, the poll() call will return once
    the timestamp is reported back to the socket error queue. (On old
    kernels around the 3.x era the poll will sleep for the full duration
    before reporting the timestamp, but this is now quite an old kernel
    release).
    
    Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>

diff --git a/config.c b/config.c
index 760b395..03d981e 100644
--- a/config.c
+++ b/config.c
@@ -324,7 +324,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("ts2phc.pulsewidth", 500000000, 1000000, 999000000),
 	PORT_ITEM_ENU("tsproc_mode", TSPROC_FILTER, tsproc_enu),
 	GLOB_ITEM_INT("twoStepFlag", 1, 0, 1),
-	GLOB_ITEM_INT("tx_timestamp_timeout", 1, 1, INT_MAX),
+	GLOB_ITEM_INT("tx_timestamp_timeout", 10, 1, INT_MAX),
 	PORT_ITEM_INT("udp_ttl", 1, 1, 255),
 	PORT_ITEM_INT("udp6_scope", 0x0E, 0x00, 0x0F),
 	GLOB_ITEM_STR("uds_address", "/var/run/ptp4l"),
diff --git a/configs/default.cfg b/configs/default.cfg
index 64ef3bd..d615610 100644
--- a/configs/default.cfg
+++ b/configs/default.cfg
@@ -51,7 +51,7 @@ hybrid_e2e		0
 inhibit_multicast_service	0
 net_sync_monitor	0
 tc_spanning_tree	0
-tx_timestamp_timeout	1
+tx_timestamp_timeout	10
 unicast_listen		0
 unicast_master_table	0
 unicast_req_duration	3600
diff --git a/ptp4l.8 b/ptp4l.8
index fe9e150..7ca3474 100644
--- a/ptp4l.8
+++ b/ptp4l.8
@@ -496,7 +496,7 @@ switches all implement this option together with the BMCA.
 .B tx_timestamp_timeout
 The number of milliseconds to poll waiting for the tx time stamp from the kernel
 when a message has recently been sent.
-The default is 1.
+The default is 10.
 .TP
 .B check_fup_sync
 Because of packet reordering that can occur in the network, in the