SG_SET_TRANSFORM 0x2204. Only is meaningful when SG_EMULATED host has yielded 1 (i.e. the low-level is the ide-scsi device driver); otherwise an EINVAL error occurs. The default state is to _not_ transform SCSI commands to the corresponding ATAPI commands but pass them straight through as is. [Only certain classes of SCSI commands need to be transformed to their ATAPI equivalents.] The third argument is interpreted as an integer. When it is non-zero then a flag is set inside the ide-scsi driver that transforms subsequent commands sent to this driver. When zero is passed as the 3rd argument to this ioctl then the flag within the ide-scsi driver is cleared and subsequent commands are not transformed. Beware, this state will affect all devices (and hence all related sg file descriptors) associated with this ide-scsi "bus".