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authorDavid S. Miller <davem@davemloft.net>2014-03-14 22:31:55 -0400
committerDavid S. Miller <davem@davemloft.net>2014-03-14 22:31:55 -0400
commit85dcce7a73f1cc59f7a96fe52713b1630f4ca272 (patch)
tree6c645923eb2f0152073b90685ce80e46cfb7afed /Documentation/networking
parent4c4e4113db249c828fffb286bc95ffb255e081f5 (diff)
parenta4ecdf82f8ea49f7d3a072121dcbd0bf3a7cb93a (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts: drivers/net/usb/r8152.c drivers/net/xen-netback/netback.c Both the r8152 and netback conflicts were simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/packet_mmap.txt2
-rw-r--r--Documentation/networking/timestamping.txt52
2 files changed, 33 insertions, 21 deletions
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index 1404674c0a02..6fea79efb4cb 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt
@@ -453,7 +453,7 @@ TP_STATUS_COPY : This flag indicates that the frame (and associated
enabled previously with setsockopt() and
the PACKET_COPY_THRESH option.
- The number of frames than can be buffered to
+ The number of frames that can be buffered to
be read with recvfrom is limited like a normal socket.
See the SO_RCVBUF option in the socket (7) man page.
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 661d3c316a17..048c92b487f6 100644
--- a/Documentation/networking/timestamping.txt
+++ b/Documentation/networking/timestamping.txt
@@ -21,26 +21,38 @@ has such a feature).
SO_TIMESTAMPING:
-Instructs the socket layer which kind of information is wanted. The
-parameter is an integer with some of the following bits set. Setting
-other bits is an error and doesn't change the current state.
-
-SOF_TIMESTAMPING_TX_HARDWARE: try to obtain send time stamp in hardware
-SOF_TIMESTAMPING_TX_SOFTWARE: if SOF_TIMESTAMPING_TX_HARDWARE is off or
- fails, then do it in software
-SOF_TIMESTAMPING_RX_HARDWARE: return the original, unmodified time stamp
- as generated by the hardware
-SOF_TIMESTAMPING_RX_SOFTWARE: if SOF_TIMESTAMPING_RX_HARDWARE is off or
- fails, then do it in software
-SOF_TIMESTAMPING_RAW_HARDWARE: return original raw hardware time stamp
-SOF_TIMESTAMPING_SYS_HARDWARE: return hardware time stamp transformed to
- the system time base
-SOF_TIMESTAMPING_SOFTWARE: return system time stamp generated in
- software
-
-SOF_TIMESTAMPING_TX/RX determine how time stamps are generated.
-SOF_TIMESTAMPING_RAW/SYS determine how they are reported in the
-following control message:
+Instructs the socket layer which kind of information should be collected
+and/or reported. The parameter is an integer with some of the following
+bits set. Setting other bits is an error and doesn't change the current
+state.
+
+Four of the bits are requests to the stack to try to generate
+timestamps. Any combination of them is valid.
+
+SOF_TIMESTAMPING_TX_HARDWARE: try to obtain send time stamps in hardware
+SOF_TIMESTAMPING_TX_SOFTWARE: try to obtain send time stamps in software
+SOF_TIMESTAMPING_RX_HARDWARE: try to obtain receive time stamps in hardware
+SOF_TIMESTAMPING_RX_SOFTWARE: try to obtain receive time stamps in software
+
+The other three bits control which timestamps will be reported in a
+generated control message. If none of these bits are set or if none of
+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_RAW_HARDWARE: report hwtimeraw if available
+
+It is worth noting that timestamps may be collected for reasons other
+than being requested by a particular socket with
+SOF_TIMESTAMPING_[TR]X_(HARD|SOFT)WARE. For example, most drivers that
+can generate hardware receive timestamps ignore
+SOF_TIMESTAMPING_RX_HARDWARE. It is still a good idea to set that flag
+in case future drivers pay attention.
+
+If timestamps are reported, they will appear in a control message with
+cmsg_level==SOL_SOCKET, cmsg_type==SO_TIMESTAMPING, and a payload like
+this:
struct scm_timestamping {
struct timespec systime;