> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf
> Of Shivani Gupta
> Sent: Saturday, August 15, 2026 3:08 AM
> To: [email protected]; Nguyen, Anthony L
> <[email protected]>; Kitszel, Przemyslaw
> <[email protected]>
> Cc: [email protected]; [email protected]; Andrew Lunn
> <[email protected]>; David S. Miller <[email protected]>; Eric
> Dumazet <[email protected]>; Jakub Kicinski <[email protected]>; Paolo
> Abeni <[email protected]>; Richard Cochran <[email protected]>;
> Simon Horman <[email protected]>; Alessio Igor Bogani
> <[email protected]>
> Subject: [Intel-wired-lan] [PATCH iwl-net] igb: Reject hwtstamp
> requests when PTP is unavailable
>
> IGB depends on PTP_1588_CLOCK_OPTIONAL, so ptp_clock_register() can
> return NULL when PTP is compiled out and can fail at runtime.
>
> Commit b888c510f7b3 ("igb: Avoid starting unnecessary workqueues")
> moved the PTP locks, work items, timestamp configuration, and clock
> reset behind successful clock registration. The netdev is already
> registered when igb_ptp_init() runs, however, and the hwtstamp entry
> points were not gated on registration. On 82576 a TX timestamp request
> can therefore schedule a never-initialized ptp_tx_work.
>
> Initialize the passive PTP state and hardware clock before registering
> the PHC. INIT_WORK() and INIT_DELAYED_WORK() do not queue any work;
> the overflow work is started only after registration succeeds. This
> also ensures that PHC callbacks and the netdev timestamping paths
> never observe partially initialized state.
>
> Reject hwtstamp get and set requests with -EOPNOTSUPP while no PTP
> clock is registered, and advertise software timestamping only in that
> state.
> Successful registration retains the existing behavior on 82576, 82580,
> i350, i354, i210, and i211. On 82575, an OFF request that was
> previously accepted as a no-op now reports that hardware timestamping
> is unsupported.
>
> Reproduced with CONFIG_IGB=y and CONFIG_PTP_1588_CLOCK=n on the QEMU
> 82576 model: SIOCSHWTSTAMP(HWTSTAMP_TX_ON) followed by a hardware
> timestamp request warned in __queue_work() before this change and
> returns EOPNOTSUPP afterwards.
>
> Fixes: b888c510f7b3 ("igb: Avoid starting unnecessary workqueues")
> Signed-off-by: Shivani Gupta <[email protected]>
> ---
> drivers/net/ethernet/intel/igb/igb_ethtool.c | 9 +++++
> drivers/net/ethernet/intel/igb/igb_ptp.c | 40 ++++++++++++++-----
> -
> 2 files changed, 38 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c
> b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> index f7938c1da835..4ebd447117cc 100644
> --- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
> +++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> @@ -2396,6 +2396,15 @@ static int igb_get_ts_info(struct net_device
> *dev,
> case e1000_i354:
> case e1000_i210:
> case e1000_i211:
> + /* No PTP clock, no hardware timestamping. Advertise
> what
> + * igb_ptp_hwtstamp_set() will actually accept.
> + */
> + if (!(adapter->ptp_flags & IGB_PTP_ENABLED)) {
> + info->so_timestamping =
> + SOF_TIMESTAMPING_TX_SOFTWARE;
> + return 0;
> + }
> +
> info->so_timestamping =
> SOF_TIMESTAMPING_TX_SOFTWARE |
> SOF_TIMESTAMPING_TX_HARDWARE |
> diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c
> b/drivers/net/ethernet/intel/igb/igb_ptp.c
> index 638d8242b66b..01992a73b37b 100644
> --- a/drivers/net/ethernet/intel/igb/igb_ptp.c
> +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
> @@ -1104,6 +1104,9 @@ int igb_ptp_hwtstamp_get(struct net_device
> *netdev, {
> struct igb_adapter *adapter = netdev_priv(netdev);
>
> + if (!(adapter->ptp_flags & IGB_PTP_ENABLED))
> + return -EOPNOTSUPP;
> +
> *config = adapter->tstamp_config;
>
> return 0;
> @@ -1285,6 +1288,9 @@ int igb_ptp_hwtstamp_set(struct net_device
> *netdev,
> struct igb_adapter *adapter = netdev_priv(netdev);
> int err;
>
> + if (!(adapter->ptp_flags & IGB_PTP_ENABLED))
> + return -EOPNOTSUPP;
> +
> err = igb_ptp_set_timestamp_mode(adapter, config);
> if (err)
> return err;
> @@ -1378,6 +1384,25 @@ void igb_ptp_init(struct igb_adapter *adapter)
> return;
> }
>
> + /* Initialize all state used by the PHC and timestamping paths
> before
> + * registering either interface. INIT_WORK() only initializes
> the work
> + * item; no work is queued until timestamping is enabled.
> + */
> + spin_lock_init(&adapter->tmreg_lock);
> + INIT_WORK(&adapter->ptp_tx_work, igb_ptp_tx_work);
> +
> + if (adapter->ptp_flags & IGB_PTP_OVERFLOW_CHECK)
> + INIT_DELAYED_WORK(&adapter->ptp_overflow_work,
> + igb_ptp_overflow_check);
> +
> + adapter->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
> + adapter->tstamp_config.tx_type = HWTSTAMP_TX_OFF;
> +
> + /* Initialize the hardware clock before ptp_clock_register()
> makes its
> + * callbacks visible. The overflow work is started after
> registration.
> + */
> + igb_ptp_reset(adapter);
> +
> adapter->ptp_clock = ptp_clock_register(&adapter->ptp_caps,
> &adapter->pdev->dev);
> if (IS_ERR(adapter->ptp_clock)) {
> @@ -1388,17 +1413,9 @@ void igb_ptp_init(struct igb_adapter *adapter)
> adapter->netdev->name);
> adapter->ptp_flags |= IGB_PTP_ENABLED;
>
> - spin_lock_init(&adapter->tmreg_lock);
> - INIT_WORK(&adapter->ptp_tx_work, igb_ptp_tx_work);
> -
> if (adapter->ptp_flags & IGB_PTP_OVERFLOW_CHECK)
> - INIT_DELAYED_WORK(&adapter->ptp_overflow_work,
> - igb_ptp_overflow_check);
> -
> - adapter->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
> - adapter->tstamp_config.tx_type = HWTSTAMP_TX_OFF;
> -
> - igb_ptp_reset(adapter);
> + schedule_delayed_work(&adapter-
> >ptp_overflow_work,
> + IGB_SYSTIM_OVERFLOW_PERIOD);
> }
> }
>
> @@ -1513,7 +1530,8 @@ void igb_ptp_reset(struct igb_adapter *adapter)
>
> wrfl();
>
> - if (adapter->ptp_flags & IGB_PTP_OVERFLOW_CHECK)
> + if ((adapter->ptp_flags & IGB_PTP_ENABLED) &&
> + (adapter->ptp_flags & IGB_PTP_OVERFLOW_CHECK))
> schedule_delayed_work(&adapter->ptp_overflow_work,
> IGB_SYSTIM_OVERFLOW_PERIOD);
> }
Reviewed-by: Aleksandr Loktionov <[email protected]>
