/* * To avoid having 1024 TDs for each isochronous transfer we introduce * a virtual frame list. Every UHCI_VFRAMELIST_COUNT entries in the real * frame list points to a non-active TD. These, in turn, form the * starts of the virtual frame list. This also has the advantage that it * simplifies linking in/out of TDs/QHs in the schedule. * Furthermore, initially each of the inactive TDs point to an inactive * QH that forms the start of the interrupt traffic for that slot. * Each of these QHs point to the same QH that is the start of control * traffic. This QH points at another QH which is the start of the * bulk traffic. * * UHCI_VFRAMELIST_COUNT should be a power of 2 and <= UHCI_FRAMELIST_COUNT. */