bttv_risc_hook
bttv_risc_hook(btv, RISC_SLOT_O_FIELD, NULL, 0);
bttv_risc_hook(btv, RISC_SLOT_O_VBI, top, top_irq_flags);
bttv_risc_hook(btv, RISC_SLOT_E_VBI, bottom, bottom_irq_flags);
bttv_risc_hook(btv, RISC_SLOT_O_FIELD, &set->top->top,
bttv_risc_hook(btv, RISC_SLOT_E_FIELD, &set->bottom->bottom,
bttv_risc_hook(btv, RISC_SLOT_O_FIELD, &set->top->top,
bttv_risc_hook(btv, RISC_SLOT_E_FIELD, NULL, 0);
bttv_risc_hook(btv, RISC_SLOT_O_FIELD, NULL, 0);
bttv_risc_hook(btv, RISC_SLOT_E_FIELD, &set->bottom->bottom,
bttv_risc_hook(btv, RISC_SLOT_O_FIELD, NULL, 0);
bttv_risc_hook(btv, RISC_SLOT_E_FIELD, NULL, 0);
int bttv_risc_hook(struct bttv *btv, int slot, struct btcx_riscmem *risc,