howto: nvidia geforce210 and 4k display

[Luigi Rizzo]

Thought this might be useful to others:

I have managed to use the nvidia geforce210 card with a 4k display
and am attaching below the relevant xorg.conf info:

--------------
    # ...

    Section "Monitor"
        Identifier   "seiki39u"
        Modeline "4k25" 225 3840 3900 3950 4000 2160 2168 2178 2250 # this is the one
        Modeline "4k30" 297 3840 4040 4240 4400 2160 2168 2178 2250
    EndSection

    Section "Device"
        Identifier  "geforce210"
        Driver      "nvidia"    # need nvidia-driver 340 or earlier
        BusID       "PCI:1:0:0"	# depends on your card
    EndSection

    Section "Screen"
        Identifier "Screen0"
        Device     "geforce210"
        Monitor    "seiki39u"
        Option "ModeValidation" "NoVertRefreshCheck, NoMaxPClkCheck, AllowNonEdidModes"
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes "4k25" # "1920x1080_30"
        EndSubSection
    EndSection

---------

Some comments:
- you need the nvidia-driver 340 or earlier, newer versions
  do not support the GeForce 210

- the card itself is not rated for 4k, and appears to have a maximum
  pixel clock frequency of 225 MHz (sometimes negotiating even just
  165 MHz with the monitor). I am using the HDMI port.

- the Modeline "4k25" can be used to run at 4k/25Hz (which is
  the most you can get with such a pixel clock). Not that you are
  losing much, since HDMI 1.3 can only to 4k/30Hz at most.

- you need to specify the Modeline because the monitor does not return
  a compatible mode through EDID (mine is a seiki TV se39uy01 - the
  very poor UK model; but i suspect others have the same issue): the
  modeline supplied by the tv uses a 297 MHz clock even at 50 Hz.

- finally, in the "Screen" section you need some options to tell
  the driver to omit certain checks:
    Option "ModeValidation" "NoVertRefreshCheck, NoMaxPClkCheck, AllowNonEdidModes"

And that's all.

	cheers
	luigi