diff options
Diffstat (limited to 'Documentation/networking/timestamping.txt')
| -rw-r--r-- | Documentation/networking/timestamping.txt | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt index bc3554124903..8b4ad809df27 100644 --- a/Documentation/networking/timestamping.txt +++ b/Documentation/networking/timestamping.txt @@ -40,7 +40,7 @@ the set bits correspond to data that is available, then the control message will not be generated: SOF_TIMESTAMPING_SOFTWARE: report systime if available -SOF_TIMESTAMPING_SYS_HARDWARE: report hwtimetrans if available +SOF_TIMESTAMPING_SYS_HARDWARE: report hwtimetrans if available (deprecated) SOF_TIMESTAMPING_RAW_HARDWARE: report hwtimeraw if available It is worth noting that timestamps may be collected for reasons other @@ -94,7 +94,13 @@ not perfect; as a consequence, sorting packets received via different NICs by their hwtimetrans may differ from the order in which they were received. hwtimetrans may be non-monotonic even for the same NIC. Filled in if SOF_TIMESTAMPING_SYS_HARDWARE is set. Requires support -by the network device and will be empty without that support. +by the network device and will be empty without that support. This +field is DEPRECATED. Only one driver computes this value. New device +drivers must leave this zero. Instead, they can expose the hardware +clock device on the NIC directly as a HW PTP clock source, to allow +time conversion in userspace and optionally synchronize system time +with a userspace PTP stack such as linuxptp. For the PTP clock API, +see Documentation/ptp/ptp.txt. SIOCSHWTSTAMP, SIOCGHWTSTAMP: |