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-rw-r--r--Documentation/networking/timestamping.txt6
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 048c92b487f6..bc3554124903 100644
--- a/Documentation/networking/timestamping.txt
+++ b/Documentation/networking/timestamping.txt
@@ -202,6 +202,9 @@ Time stamps for outgoing packets are to be generated as follows:
202 and not free the skb. A driver not supporting hardware time stamping doesn't 202 and not free the skb. A driver not supporting hardware time stamping doesn't
203 do that. A driver must never touch sk_buff::tstamp! It is used to store 203 do that. A driver must never touch sk_buff::tstamp! It is used to store
204 software generated time stamps by the network subsystem. 204 software generated time stamps by the network subsystem.
205- Driver should call skb_tx_timestamp() as close to passing sk_buff to hardware
206 as possible. skb_tx_timestamp() provides a software time stamp if requested
207 and hardware timestamping is not possible (SKBTX_IN_PROGRESS not set).
205- As soon as the driver has sent the packet and/or obtained a 208- As soon as the driver has sent the packet and/or obtained a
206 hardware time stamp for it, it passes the time stamp back by 209 hardware time stamp for it, it passes the time stamp back by
207 calling skb_hwtstamp_tx() with the original skb, the raw 210 calling skb_hwtstamp_tx() with the original skb, the raw
@@ -212,6 +215,3 @@ Time stamps for outgoing packets are to be generated as follows:
212 this would occur at a later time in the processing pipeline than other 215 this would occur at a later time in the processing pipeline than other
213 software time stamping and therefore could lead to unexpected deltas 216 software time stamping and therefore could lead to unexpected deltas
214 between time stamps. 217 between time stamps.
215- If the driver did not set the SKBTX_IN_PROGRESS flag (see above), then
216 dev_hard_start_xmit() checks whether software time stamping
217 is wanted as fallback and potentially generates the time stamp.