Re: [Intel-wired-lan] [PATCH 8/9] ice: restore timestamp configuration after reset

[Jacob Keller <jacob.e.keller@intel.com>]

On 8/7/2023 3:36 AM, Karol Kolacinski wrote:
> The driver calls ice_ptp_cfg_timestamp() during
> ice_ptp_prepare_for_reset() to disable timestamping while the device is
> resetting. It then attempts to restore timestamp configuration at the
> end of ice_rebuild(). However, it currently forcibly calls
> ice_ptp_cfg_timestamp() with a value of true when the device is not E810
> and is the clock owner, while calling ice_ptp_cfg_timestamp() with a
> value of false for all other devices.
> 
> This incorrectly forcibly disables timestamping on all ports except the
> clock owner.
> 
> This was not detected previously due to a quirk of the LinuxPTP ptp4l
> application. If ptp4l detects a missing timestamp, it enters a fault
> state and performs recovery logic which includes executing SIOCSHWTSTAMP
> again, restoring the now accidentally cleared configuration.
> 
> Not every application does this, and for these applications, timestamps
> will mysteriously stop after a PF reset, without being restored until an
> application restart.
> 
> Fix this by replacing ice_ptp_cfg_timestamp() with two new functions:
> 
> 1) ice_ptp_disable_timestamp_mode() which unconditionally disables the
>    timestamping logic in ice_ptp_prepare_for_reset() and
>    ice_ptp_release()
> 
> 2) ice_ptp_restore_timestamp_mode() which calls
>    ice_ptp_restore_tx_interrupt() to restore Tx timestamping
>    configuration, calls ice_set_rx_tstamp() to restore Rx timestamping
>    configuration, and issues an immediate TSYN_TX interrupt to ensure
>    that timestamps which may have occurred during the device reset get
>    processed.
> 
> This obsoletes the ice_set_tx_tstamp() function which can now be safely
> removed.
> 
> With this change, all devices should now restore Tx and Rx timestamping
> functionality correctly after a PF reset without application
> intervention.
> 
> Change-type: DefectResolution
> HSDES-number: 22018443364
> HSDES-tenant: server_platf_lan.bug
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> ---

I'm sending a version of this patch directly to net-next along with the
related fix for PFINT_TSYN_MSK, so that may cause a conflict with this
series. I think it should be fixable by Tony or myself when we rebase
IWL, but it could lead to needing a new version of the series.

Thanks,
Jake
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