Service_USB 8 - Sub host controller removed — Used for communications between USB Host Controller drivers. Shows that a sub host controller driver has been removed.
| R0 | 8 (reason code) |
| R1 | &80C00 (USB Service call) |
| R2 | Pointer to a list of sub driver properties, used as a unique tag. |
Some Host controller drivers are split into two parts a generic device type handler and a specific hardware dependent support module. This allows one host controller type to have numerous differing hardware implementations without needless duplication of code.
This service call is issued by a main host class driver before it is removed. This allows any sub drivers to perform any necessary finalisation. The sub driver may claim the service to prevent the host class drivers removal.