Re: [Linuxptp-users] Support for latest igb driver?

[Richard C. <ric...@gm...>]

On Wed, Dec 21, 2016 at 04:26:16PM -0500, Rich Schmidt wrote:
> I've been testing linuxptp for about a year (now version 1.8) and am still
> seeing the following failure always after 8 or more days of successful
> operation:

> ptp4l[4906544.301]: port 1: delay timeout
> ptp4l[4906545.303]: timed out while polling for tx timestamp
> ptp4l[4906545.303]: increasing tx_timestamp_timeout may correct this issue,
> but it is likely cause
> d by a driver bug
> ptp4l[4906545.303]: port 1: send delay request failed

I don't recalling seeing this myself, but still this is the second
such igb failure report I have received recently.

I wonder whether the incorrect double TSICR acknowledge is the root
cause.  In igb_main.c we have:

static void igb_tsync_interrupt(struct igb_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;
	struct ptp_clock_event event;
	struct timespec64 ts;
	u32 ack = 0, tsauxc, sec, nsec, tsicr = rd32(E1000_TSICR);

	...

	/* acknowledge the interrupts */
	wr32(E1000_TSICR, ack);
}

According to the datasheet, the first rd32() should already
acknowledge the interrupts, but the 82580 (iirc) has a bug that
requires the additional wr32().

Try removing that last line, and see if things improve...

Thanks,
Richard