[Intel-wired-lan] [iwl-net v1 0/2] igc/igb: Fix missing time sync events

[Vinicius Costa Gomes <vinicius.gomes@intel.com>]

Hi,

It was reported that i225/i226 could sometimes miss some time sync
events when two or more types of events (PPS and Timestamps was used
by the reporter) are being used at the same time under heavy traffic.

The core issue is that the driver was double clearing interrupts, as
the register is both "read to clear" and "write 1 to clear"
(documented in section 8.16.1 of the datasheet), and the handler was
doing both. Which could cause events to be missed if they happen
between the "read" and the "write".

Removing the write fixes the issue.

It was tracked down to commit 2c344ae24501 ("igc: Add support for TX
timestamping"), in which I added support for basic timestamp
operations, the issue is that as the hardware operates very similarly
to i210, I used igb code as inspiration. And indeed, the same double
clearing is present there.

But in the igb case, I haven't seen myself or heard about any issues
that seem related to this. So I think it's more like a possible issue.
But it seems like a good idea to fix it there was well.


Vinicius Costa Gomes (2):
  igc: Fix missing time sync events
  igb: Fix missing time sync events

 drivers/net/ethernet/intel/igb/igb_main.c | 23 +++++------------------
 drivers/net/ethernet/intel/igc/igc_main.c | 12 +-----------
 2 files changed, 6 insertions(+), 29 deletions(-)

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2.43.2