M4 停不下来

root@myd-am62x:~#  cat /sys/class/remoteproc/remoteproc0/state
running
root@myd-am62x:~#  echo stop > /sys/class/remoteproc/remoteproc0/state
[  113.811353] k3-m4-rproc 5000000.m4fss: k3_m4_rproc_stop: timedout waiting for rproc completion event
[  113.820681] remoteproc remoteproc0: can't stop rproc: -16
-sh: echo: write error: Device or resource busy
root@myd-am62x:~#  echo stop > /sys/class/remoteproc/remoteproc0/state
[  122.771017] k3-m4-rproc 5000000.m4fss: k3_m4_rproc_stop: timedout waiting for rproc completion event
[  122.780331] remoteproc remoteproc0: can't stop rproc: -16
-sh: echo: write error: Device or resource busy
root@myd-am62x:~#  echo stop > /sys/class/remoteproc/remoteproc0/state
[  138.648588] k3-m4-rproc 5000000.m4fss: k3_m4_rproc_stop: timedout waiting for rproc completion event
[  138.657945] remoteproc remoteproc0: can't stop rproc: -16
-sh: echo: write error: Device or resource busy
root@myd-am62x:~#