dasd-eckd.120e7f <bus ID of the DASD>: Channel path <logical path mask> lost HPF functionality and is disabled
Explanation
A channel path has lost High Performance FICON (HPF) functionality
and was removed from regular operations.
User response
Report the problem to your support organization.
Ensure that the cabling between the storage server and the mainframe
system is securely in place.
Reset the device and channel paths by writing "all" or a logical path mask
to the path_reset sysfs attribute of the device.