Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...

[linux-drm-fsl-dcu.git] / Documentation / networking / timestamping.txt

diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 98097d8cb910ba9d42f25e7860bec06e61a89faa..661d3c316a17721d787a8a601f3e9c8356e957be 100644 (file)
--- 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