Commit cd7f7328 authored Apr 01, 2025 by Christopher S M Hall Committed by Tony Nguyen Apr 11, 2025

igc: move ktime snapshot into PTM retry loop



Move ktime_get_snapshot() into the loop. If a retry does occur, a more
recent snapshot will result in a more accurate cross-timestamp.

Fixes: a90ec848 ("igc: Add support for PTP getcrosststamp()")
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Mor Bar-Gabay <morx.bar.gabay@intel.com>
Tested-by: Avigail Dahan <avigailx.dahan@intel.com>
Signed-off-by: Christopher S M Hall <christopher.s.hall@intel.com>
Reviewed-by: Corinna Vinschen <vinschen@redhat.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

parent 714cd033

drivers/net/ethernet/intel/igc/igc_ptp.c

+9 −9

Original line number	Diff line number	Diff line
		@@ -1011,16 +1011,16 @@ static int igc_phc_get_syncdevicetime(ktime_t *device,
		int err, count = 100;
		ktime_t t1, t2_curr;

		/* Get a snapshot of system clocks to use as historic value. */
		ktime_get_snapshot(&adapter->snapshot);

		do {
		/* Doing this in a loop because in the event of a
		* badly timed (ha!) system clock adjustment, we may
		* get PTM errors from the PCI root, but these errors
		* are transitory. Repeating the process returns valid
		* data eventually.
		*/
		do {
		/* Get a snapshot of system clocks to use as historic value. */
		ktime_get_snapshot(&adapter->snapshot);

		igc_ptm_trigger(hw);

		err = readx_poll_timeout(rd32, IGC_PTM_STAT, stat,