Lines Matching +full:touch +full:- +full:hold +full:- +full:ms
1 .. SPDX-License-Identifier: GPL-2.0
43 -------------------------------------------------------------
59 -------------------------------------------------------------------
63 timeval of SO_TIMESTAMP (ms).
72 ----------------------------------------------------------------------
138 over-report measurement, because the timestamp is generated when all
189 is derived from a per-socket u32 counter (that wraps). For datagram
212 cmsg->cmsg_level = SOL_SOCKET;
213 cmsg->cmsg_type = SCM_TS_OPT_ID;
214 cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
230 a timestamp with counter N-1. SOF_TIMESTAMPING_OPT_ID_TCP
280 received the packet and its length at layer 2. A valid (non-zero)
305 ignore the unexpected non-zero value. But it makes behavior subtly
332 cmsg->cmsg_level = SOL_SOCKET;
333 cmsg->cmsg_type = SO_TIMESTAMPING;
334 cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
352 -------------------------
362 correlating a timestamp with data is non-trivial. A range of bytes
391 relevant sequence number in skb_shinfo(skb)->tskey. Because an skbuff
400 autocork. After linux-4.7, a better way to prevent coalescing is
422 ----------------------------
445 feature. At least one field is non-zero at any time. Most timestamps
448 ts[1] used to hold hardware timestamps converted to system time.
452 as linuxptp. For the PTP clock API, see Documentation/driver-api/ptp.rst.
489 is the first if ts[2] is non-zero, the second otherwise, in which
517 Reading from the error queue is always a non-blocking operation. To
582 If the requested fine-grained filtering for incoming packets is not
589 /* possible values for hwtstamp_config->tx_type */
607 /* possible values for hwtstamp_config->rx_filter */
627 --------------------------------------------------------
648 - In hard_start_xmit(), check if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)
649 is set no-zero. If yes, then the driver is expected to do hardware time
651 - If this is possible for the skb and requested, then declare
653 SKBTX_IN_PROGRESS in skb_shinfo(skb)->tx_flags , e.g. with::
655 skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
659 do that. A driver must never touch sk_buff::tstamp! It is used to store
661 - Driver should call skb_tx_timestamp() as close to passing sk_buff to hardware
664 - As soon as the driver has sent the packet and/or obtained a
676 ----------------------------------------------------------
717 - ``.port_txtstamp()``: a hook called prior to the transmission of
719 This is required for two-step timestamping, since the hardware
722 packet so that it can re-enqueue the packet back into the socket's
725 in skb->cb and enqueue a tx skb queue. Typically, a switch will have a
728 key-value pairs of PTP sequence ID/message type/domain number and the
736 One-step TX timestamping do not require packet cloning, since there is
737 no follow-up message required by the PTP protocol (because the
740 to be re-enqueued into its socket's error queue.
742 - ``.port_rxtstamp()``: On RX, the BPF classifier is run by DSA to
747 timestamps might either be available in-band (through metadata in the
748 DSA header, or attached in other ways to the packet), or out-of-band
764 mii_timestamper`` and add a pointer to it in ``phydev->mii_ts``. The presence
772 - Checking, in ``.ndo_eth_ioctl``, whether ``phy_has_hwtstamp(netdev->phydev)``
776 - On RX, special intervention may or may not be needed, depending on the
779 ``skb_defer_rx_timestamp(skb)`` is necessary or not - and if it is, don't
781 enabled, and ``skb->dev->phydev->mii_ts`` exists, its ``.rxtstamp()`` hook
792 - On TX, again, special intervention might or might not be needed. The
793 function that calls the ``mii_ts->txtstamp()`` hook is named
814 Stacked PHCs, especially DSA (but not only) - since that doesn't require any
816 all possible code paths - is that they uncover bugs which were impossible to
820 skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
831 the ``.ndo_eth_ioctl`` ("``priv->hwtstamp_tx_enabled == true``") and the
832 current skb requires a TX timestamp ("``skb_shinfo(skb)->tx_flags &
834 "``skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS``" flag. Note: as
842 "``skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS``" was set. With a stacked
849 "``skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS``", but also for
850 "``priv->hwtstamp_tx_enabled == true``". Because the rest of the system ensures