elmcan_netdev_start_xmit(): Remove unnecessary skb->len check

[elmcan.git] / readme.rst

diff --git a/readme.rst b/readme.rst
index 408c6911663aeb4c8e9afd8f6c248a3a779bddd9..e3792211b6c172ae506f7f073b0517e715250bec 100644 (file)
--- a/readme.rst
+++ b/readme.rst
@@ -105,6 +105,20 @@ The line discipline can be attached on a command prompt as follows::
 To change the ELM327's serial settings, please refer to its data
 sheet. This needs to be done before attaching the line discipline.
 
+Once the ldisc is attached, the CAN interface starts out unconfigured.
+Set the speed before starting it:
+
+    # The interface needs to be down to change parameters
+    sudo ip link set can0 down
+    sudo ip link set can0 type can bitrate 500000
+    sudo ip link set can0 up
+
+500000 bit/s is a common rate for OBD-II diagnostics.
+If you're connecting straight to a car's OBD port, this is the speed
+that most cars (but not all!) expect.
+
+After this, you can set out as usual with candump, cansniffer, etc.
+
 
 
 Known limitations of the controller
@@ -162,8 +176,8 @@ Known limitations of the controller
 - Versions prior to 1.3
 
   These chips cannot be used at all with elmcan. They do not support
-  the "``AT D1``", which is necessary to avoid parsing conflicts on
-  incoming data, as well as distinction of RTR frame lengths.
+  the "``AT D1``" command, which is necessary to avoid parsing conflicts
+  on incoming data, as well as distinction of RTR frame lengths.
 
   Specifically, this allows for easy distinction of SFF and EFF
   frames, and to check whether frames are complete. While it is possible