echo 0 > /sys/kernel/debug/tracing/tracing_on
cd /sys/kernel/tracing/
echo 'gether_*' > set_ftrace_filter
echo 'eem_*' >> set_ftrace_filter
echo 'composite_*' >> set_ftrace_filter
echo 'usb_fun*' >> set_ftrace_filter
echo '*configfs_*' >> set_ftrace_filter
echo 'reset_config' >> set_ftrace_filter
echo function > current_tracer
echo 1 > /sys/kernel/debug/tracing/tracing_on

echo 0 > /sys/kernel/debug/tracing/tracing_on
cat trace

***************************

root@yuna:~# echo 0 > /sys/kernel/debug/tracing/tracing_on
root@yuna:~# cd /sys/kernel/tracing/
root@yuna:/sys/kernel/tracing# echo 'gether_*' > set_ftrace_filter
root@yuna:/sys/kernel/tracing# echo 'eem_*' >> set_ftrace_filter
root@yuna:/sys/kernel/tracing# echo function > current_tracer
root@yuna:/sys/kernel/tracing# echo 'reset_config' >> set_ftrace_filter
root@yuna:/sys/kernel/tracing# echo 1 > /sys/kernel/debug/tracing/tracing_on
-> switch to host mode
root@yuna:/sys/kernel/tracing# ifconfig
lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 84  bytes 7969 (7.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 84  bytes 7969 (7.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.42.0.221  netmask 255.255.255.0  broadcast 10.42.0.255
        inet6 fe80::a8bb:ccff:fedd:eef1  prefixlen 64  scopeid 0x20<link>
        ether aa:bb:cc:dd:ee:f1  txqueuelen 1000  (Ethernet)
        RX packets 76  bytes 10201 (9.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 96  bytes 12782 (12.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlan0: flags=-28669<UP,BROADCAST,MULTICAST,DYNAMIC>  mtu 1500
        ether fc:c2:de:3b:0b:aa  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
->switch to device mode
root@yuna:/sys/kernel/tracing#
root@yuna:/sys/kernel/tracing# echo 0 > /sys/kernel/debug/tracing/tracing_on
root@yuna:/sys/kernel/tracing# cat trace
# tracer: function
#
# entries-in-buffer/entries-written: 53/53   #P:2
#
#                                _-----=> irqs-off/BH-disabled
#                               / _----=> need-resched
#                              | / _---=> hardirq/softirq
#                              || / _--=> preempt-depth
#                              ||| / _-=> migrate-disable
#                              |||| /     delay
#           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
#              | |         |   |||||     |         |
     irq/68-dwc3-523     [000] D..3.   133.990254: reset_config <-__composite_disconnect
     irq/68-dwc3-523     [000] D..3.   133.992274: eem_disable <-reset_config
     irq/68-dwc3-523     [000] D..3.   133.992276: gether_disconnect <-reset_config
     kworker/1:3-443     [001] ...1.   134.022453: eem_unbind <-purge_configs_funcs

-> to device mode

     kworker/1:3-443     [001] ...1.   148.630773: eem_bind <-usb_add_function
     irq/68-dwc3-734     [000] D..3.   149.155209: eem_set_alt <-composite_setup
     irq/68-dwc3-734     [000] D..3.   149.155215: gether_disconnect <-eem_set_alt
     irq/68-dwc3-734     [000] D..3.   149.155220: gether_connect <-eem_set_alt
     irq/68-dwc3-734     [000] D..3.   149.157287: eem_set_alt <-composite_setup
     irq/68-dwc3-734     [000] D..3.   149.157292: gether_disconnect <-eem_set_alt
     irq/68-dwc3-734     [000] D..3.   149.159338: gether_connect <-eem_set_alt
     irq/68-dwc3-734     [000] D..2.   149.239625: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.250382: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.250428: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.324788: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.335868: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.338353: eem_unwrap <-rx_complete
     kworker/0:2-59      [000] D..4.   149.347366: eem_wrap <-eth_start_xmit
     irq/68-dwc3-734     [000] D..2.   149.574459: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.585781: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.585835: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.585854: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.693658: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.753604: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   149.835828: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.035467: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.037722: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.104841: eem_unwrap <-rx_complete
     kworker/0:2-59      [000] D..4.   150.112697: eem_wrap <-eth_start_xmit
     irq/68-dwc3-734     [000] D..2.   150.336997: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.371259: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.529462: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.548360: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.548405: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.723972: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.775950: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   150.779898: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   151.082055: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   151.083955: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   151.084065: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   151.236544: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   151.510781: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   152.335332: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   152.336159: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   152.416075: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   152.418412: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   153.126692: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   153.128929: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   153.128981: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   153.233421: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   156.331637: eem_unwrap <-rx_complete
     irq/68-dwc3-734     [000] D..2.   156.331692: eem_unwrap <-rx_complete
          <idle>-0       [001] DNs5.   156.960603: eem_wrap <-eth_start_xmit
