python-can CanError: Transmit buffer full

[zymouse]

[ERROR] [1648717364.434832]: bad callback: <function callback at 0x7fb54c4550>
Traceback (most recent call last):
  File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/home/nvidia/ros_driver/catkin_ws_control/src/pix_driver/src/canbus_talker.py", line 47, in callback
    bus.send(send_message)
  File "build/bdist.linux-aarch64/egg/can/interfaces/socketcan/socketcan.py", line 665, in send
    raise can.CanError("Transmit buffer full")
CanError: Transmit buffer full

原因分析

这是一种，不带电阻的can卡硬件，经常出现的问题。当can线没有接到任何can网络上或者没有can0和can1相连连上时。这时
can硬件是没有在网络上的，就无法发生数据了。

# 这个时候
$ cangen can0
$ candump can0 # 看不见任何数据

解决办法

can线接到任何can网络上
或者
can0和can1相接