Re: [Linuxptp-users] Question about meanPathDelay (possible bug?)

[Wolfgang W. <wol...@gm...>]

On Wed, 31 Jul 2013 16:32:56 +0200, Richard Cochran  
<ric...@gm...> wrote:

> On Wed, Jul 31, 2013 at 10:41:07AM +0200, Wolfgang Wallner wrote:
>> I did not think of the possibility that the lower layer puts the value  
>> of
>> delay_resp.receiveTimestamp into this field.
>
> pdu = protocol data unit, here protocol means the PTP.
>
> There is a long comment in msg.h that describes the time stamp fields.

Do you mean the following comment?

	struct {
		/**
		 * Contains the time stamp from the packet data in a
		 * native binary format for the host machine. The
		 * exact source of the time stamp's value depends on
		 * the message type:
		 *
		 * - announce    originTimestamp
		 * - follow_up   preciseOriginTimestamp
		 * - sync        originTimestamp
		 * - delay_req   originTimestamp
		 * - pdelay_resp     requestReceiptTimestamp
		 * - pdelay_resp_fup responseOriginTimestamp
		 */
		struct timestamp pdu;
		/**
		 * Approximate ingress time stamp using the relative
		 * CLOCK_MONOTONIC. Used to determine when announce
		 * messages have expired.
		 */
		struct timespec host;
	} ts;

This comment does not fully match the behavior in the  
msg_post_recv()-function , as timestamps of delay_req-frames are not  
handled in this functions, and delay_resp-frames are missing in the  
comment description.
IMHO it would be more accurate to replace the delay_req-line with  
"delay_resp  receiveTimestamp".

regards, Wolfgang