STRUCT ICE_TX_TSTAMP(9)

💅 struct ice_tx_tstamp(9) 💅

okay bestie, welcome to the Kernel API Manual — today's main character is struct ice_tx_tstamp, and she's literally just here to keep track of a single Tx timestamp request. no cap. ✨

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🌸 NAME 🌸

struct ice_tx_tstamp — Tracking for a single Tx timestamp 🕐

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🦋 SYNOPSIS 🦋

struct ice_tx_tstamp {
    struct sk_buff *skb;
    unsigned long start;
    u64 cached_tstamp;
 };

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🎀 MEMBERS 🎀

• skb — pointer to the SKB for this timestamp request 🫶 (this is the one you hand over when you kick off a request)
• start — jiffies when the timestamp was first requested ⏱️
• cached_tstamp — last read timestamp 💾 like, the timestamp you read most recently, saved for later

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✨ DESCRIPTION ✨

So this structure tracks a single timestamp request — that's her whole job, and she ate. 💅 The SKB pointer is provided when initiating a request.

The start time is used to ensure that we discard old requests that were not fulfilled within a 2 second time window. 👋 bye stale requests, you had your 2 seconds, no hard feelings.

Timestamp values in the PHY are read only and do not get cleared except at hardware reset or when a new timestamp value is captured. like, they're not doing the whole "reset after you read me" thing — rude but fine. 🫠

Some PHY types do not provide a "ready" bitmap indicating which timestamp indexes are valid. 😭 In these cases, we use a cached_tstamp to keep track of the last timestamp we read for a given index. If the current timestamp value is the same as the cached value, we assume a new timestamp hasn't been captured. This avoids reporting stale timestamps to the stack. and that's the whole point — no stale data on our watch, periodt. 🔥

ngl this check only happens if the has_ready_bitmap flag is not set in ice_ptp_tx structure. no flag, no bitmap, cached value does the vibe check instead. 🧚

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👑 SEE ALSO 👑

• Kernel file ./drivers/net/ethernet/intel/ice/ice_ptp.h enum ice_tx_tstamp_work(9)
• struct ice_ptp_tx(9)
• struct ice_ptp_port(9)
• struct ice_ptp_pin_desc(9)
• struct ice_ptp(9)

all the girlies in the same friend group, iykyk 💜

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and that's the page!! 🌈 shoutout to ./drivers/net/ethernet/intel/ice and the October 2026 date stamp — this one's from the Kernel API Manual, mwah 💋 🎀