Hi,
Since my VIA based hardware wasn't attaching a unichrome driver, I decided to take a look at it. After investigation, I found out that the driver had been mainly unfinished:
* It matches only one unichrome graphics ID from (CN700 and related chipsets) and have some hard coded values referencing it here and there (also, erratically driver refers to graphics from non existent CN900 chipset in few places, including pcidevs, likely CN700 was meant).
* The code itself has definitions for some other unichrome graphics from CN400, CLE266 (and related) chipsets but not the newer ones (VX800/VX855/VX900).
* Not included in amd64 ports, similarly to some other VIA specific hardware drivers.
* It is mentioned in amd64 ALL configuration but without wsdisplay* at unichromefb?. Likely leftover from i386 and should be removed for now, same as viadrmums (which causes system to crash in amd64, at least on VX800/900).
* Driver was made compatible with the legacy viadrm driver but it doesn't seem to work with viadrmums. My system crashed spectacularly once both enabled.
It successfully attached and booted with higher resolution for me on CN400 unichrome graphics, once I added its ID without any other modifications. So, I believe, adding support for all unichrome drivers should not be too hard. Not sure why it was abandoned and what was unfinished though.
So out of that I am planning to create PRs unless someone can look at those:
* Add support for all unichrome graphics (possibly can take a look at this)...
* Make it compatible with viadrmums as it was with viadrm, if that possible.
Besides that I believe tha viadrmums and unichromefb should be removed from amd64 ALL kernel configuration, at least for now. And
CN900 should be renamed to CN700 in all places.
Regards,
Andrius V