On 11/27/2025 9:01 AM, Loktionov, Aleksandr wrote:
-----Original Message-----
From: Intel-wired-lan <[email protected]> On Behalf Of
Vitaly Lifshits
Sent: Thursday, November 27, 2025 5:31 AM
To: [email protected]; [email protected];
[email protected]; [email protected]; [email protected];
[email protected]; [email protected]; [email protected]
Cc: Lifshits, Vitaly <[email protected]>
Subject: [Intel-wired-lan] [PATCH iwl-next v1 1/1] e1000e: introduce private
flag to override XTAL clock frequency
On some TGP and ADP systems, the hardware XTAL clock is incorrectly set to
Please expand platform abbreviations ("TGP (Tiger Lake PCH)", "ADP (Alder Lake
PCH)") and add minimal test context (kernel ver., device PCI ID, FW, phc_ctl version, and
whether CLOCK_REALTIME vs PHC was compared).
Thanks, I'll address this in v2.
24MHz instead of the expected 38.4MHz, causing PTP timer inaccuracies. Since
affected systems cannot be reliably detected, introduce an ethtool private
flag that allows user-space to override the XTAL clock frequency.
Tested on an affected system using the phc_ctl tool:
Without the flag:
sudo phc_ctl enp0s31f6 set 0.0 wait 10 get
phc_ctl[...] clock time is 16.000541250 (expected ~10s)
With the flag:
sudo phc_ctl enp0s31f6 set 0.0 wait 10 get
phc_ctl[...] clock time is 9.984407212 (expected ~10s)
If the XTAL override is applied via a devlink driverinit param, this reset is
expected and should be documented.
If it remains a runtime privflag, I think you should explain why a reset is
required.
I'd recommend documenting the reset requirement and user impact (link flap,
timestamp discontinuity).
/* Add a short comment near the reset logic in code and
Documentation/networking/devlink/e1000e.rst (if converted to devlink param)
Or Documentation/networking/ethtool-netlink.rst (if kept as privflag) */
Though your comment might become irrelevant if Andrew's detection
approach works, I'll still clarify the reset behavior. e1000e is a
legacy driver and does not support devlink, so the override remains a
runtime privflag. A reset is currently required to reconfigure PTP
parameters with the new timinca value.
Signed-off-by: Vitaly Lifshits <[email protected]>
---
drivers/net/ethernet/intel/e1000e/e1000.h | 7 ++--
drivers/net/ethernet/intel/e1000e/ethtool.c | 39 ++++++++++-----------
drivers/net/ethernet/intel/e1000e/ich8lan.c | 4 +--
drivers/net/ethernet/intel/e1000e/netdev.c | 18 +++++++---
4 files changed, 39 insertions(+), 29 deletions(-)
...
--
2.34.1
