GEN4_LINK_CTRL_LINK_DISABLE
lnkctl |= GEN4_LINK_CTRL_LINK_DISABLE;
lnkctl &= ~GEN4_LINK_CTRL_LINK_DISABLE;
lnkctl |= GEN4_LINK_CTRL_LINK_DISABLE;
return ((cntl & GEN4_LINK_CTRL_LINK_DISABLE) == 0);