[iwl-net,v2,0/4] igc: Fix PTM timeout

Message

Hall, Christopher S Oct. 23, 2024, 2:30 a.m. UTC

There have been sporadic reports of PTM timeouts using i225/i226 devices

These timeouts have been root caused to:

1) Manipulating the PTM status register while PTM is enabled and triggered
2) The hardware retrying too quickly when an inappropriate response is
   received from the upstream device

The issue can be reproduced with the following:

$ sudo phc2sys -R 1000 -O 0 -i tsn0 -m

Note: 1000 Hz (-R 1000) is unrealistically large, but provides a way to
quickly reproduce the issue.

PHC2SYS exits with:

"ioctl PTP_OFFSET_PRECISE: Connection timed out" when the PTM transaction
  fails

Changelog:

v1 -> v2: -Removed patch modifying PTM retry loop count
      	  -Moved PTM mutex initialization from igc_reset() to igc_ptp_init()
	   called once in igc_probe()


Christopher S M Hall (4):
  igc: Ensure the PTM cycle is reliably triggered
  igc: Lengthen the hardware retry time to prevent timeouts
  igc: Move ktime snapshot into PTM retry loop
  igc: Add lock preventing multiple simultaneous PTM transactions

 drivers/net/ethernet/intel/igc/igc.h         |  1 +
 drivers/net/ethernet/intel/igc/igc_defines.h |  3 +-
 drivers/net/ethernet/intel/igc/igc_ptp.c     | 98 ++++++++++++--------
 3 files changed, 62 insertions(+), 40 deletions(-)