-A reIPL is the first approach to reset the CHPids
-If reIPL does not work check your MIHTimeoutValue parm in your VTParms startup options.
When MIHTimeoutValue is set to the value of -1, CA Vtape VTS will not set the MIH timeout. The default value is 15 but it can be adjusted all the way up to 9999
The MIH timeout interval is dependent on environmental conditions like DASD cache volume response times and the number of chained CCW’s in an I/O channel program. If DASD cache volume response times are high or applications like DB2 or Syncsort are writing to Virtual Volumes, a higher value for this attribute will be required. We recommend a setting of 30 seconds.
In general, this attribute should not be set to a value higher than 60 seconds without first discussing the change with CA Technical Support.
-After that you will need to send in dumps and any Vtape IPCS trace at the time the devices first got boxed.