CHSC subchannel device driver
The CHSC subchannel device driver provides a means for user space programs to obtain information about the machine setup and to perform asynchronous channel subsystem calls that modify the machine setup.
From a designated LPAR with special privileges, you can issue asynchronous channel subsystem calls. With these calls, you can dynamically change the I/O configuration of the machine.
The CHSC subchannel device driver implements an interface to issue synchronous and asynchronous CHSC calls. Control blocks for the calls must be built in user space.
What you should know about the CHSC subchannel device driver
The CHSC subchannel device driver binds to any CHSC subchannels that are found on the css bus. No special attributes are created; and, unlike other subchannel types, no second-level device is registered.
CHSC subchannels are automatically enabled when the CHSC subchannel device driver binds to them. There is no user interface for enabling or disabling CHSC subchannels.