igc: move ktime snapshot into PTM retry loop

[ Upstream commit cd7f7328d691937102732f39f97ead35b15bf803 ]

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: a90ec84837 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Christopher S M Hall
2025-04-01 16:35:31 -07:00
committed by Greg Kroah-Hartman
parent b1f3e69dc9
commit 5262d34f5e

View File

@@ -980,16 +980,16 @@ 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);
/* 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 {
/* 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.
*/
/* 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,