So I have a T410s with an LVDS panel and switchable graphics between intel and nvidia. I've gotten the basic switching support just like we have on the intel/amd combination.
The code is a start towards generic nvidia/nvidia and intel/nvidia switching but its missing some bits. The MUX switch on some GPUs relies on passing a parameter to the WMI function that we aren't passing, luckily the lenovo doesn't need this parameter at the moment so it works fine. Other laptops in this range may require the parameter.
I'll try and get some more info on the magic value we need to pass on other systems to make it work better, other systems like the Sony Vaios have a number of muxable outputs listed in a table, that the intel acpi code prints out at drm.debug=0x4. Again the lenovo doesn't have this table.
once switched and powered off the Intel, we get log spam from the IPS driver about the MCP limits.
nouveau gets a 1024x768 console since we can't detect the LVDS panel at startup.
also, this only works with open source drivers, i915 and nouveau.