diff options
Diffstat (limited to 'Documentation/networking/timestamping.txt')
| -rw-r--r-- | Documentation/networking/timestamping.txt | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt index 98097d8cb910..661d3c316a17 100644 --- a/Documentation/networking/timestamping.txt +++ b/Documentation/networking/timestamping.txt @@ -85,7 +85,7 @@ Filled in if SOF_TIMESTAMPING_SYS_HARDWARE is set. Requires support by the network device and will be empty without that support. -SIOCSHWTSTAMP: +SIOCSHWTSTAMP, SIOCGHWTSTAMP: Hardware time stamping must also be initialized for each device driver that is expected to do hardware time stamping. The parameter is defined in @@ -115,6 +115,10 @@ Only a processes with admin rights may change the configuration. User space is responsible to ensure that multiple processes don't interfere with each other and that the settings are reset. +Any process can read the actual configuration by passing this +structure to ioctl(SIOCGHWTSTAMP) in the same way. However, this has +not been implemented in all drivers. + /* possible values for hwtstamp_config->tx_type */ enum { /* @@ -157,7 +161,8 @@ DEVICE IMPLEMENTATION A driver which supports hardware time stamping must support the SIOCSHWTSTAMP ioctl and update the supplied struct hwtstamp_config with -the actual values as described in the section on SIOCSHWTSTAMP. +the actual values as described in the section on SIOCSHWTSTAMP. It +should also support SIOCGHWTSTAMP. Time stamps for received packets must be stored in the skb. To get a pointer to the shared time stamp structure of the skb call skb_hwtstamps(). Then |