CRTC_OFFSET
aty_st_le32(CRTC_OFFSET, offset);
aty_st_le32(CRTC_OFFSET, crtc->offset);
OUTREG(CRTC_OFFSET, 0);
OUTREG(CRTC_OFFSET, (var->yoffset * info->fix.line_length +
OUTREG(CRTC_OFFSET, 0);