Ultra HD 4K Linux Graphics Card Testing
With the AMD Radeon HD 7000 series and newer is where it's possible to drive a 4096 x 2160 display. The DisplayPort 1.2 connections on the newer AMD graphics cards support a resolution up to 4096 x 2160 at 60Hz. The HDMI connectors on the AMD graphics cards support a resolution as well up to 4096 x 2160, but the HDMI 1.4 specification is limited to a refresh rate of just 30Hz. The Seiki SE39UY04 only has HDMI 1.4 connections with no DisplayPort connectivity. On the NVIDIA side you need a GeForce 600 "Kepler" graphics card or newer to drive a display up to 4096 x 2160. With Intel graphics it's possible for Ivy Bridge and Haswell graphics processors to drive 4K resolutions, but we didn't test any Intel GPU at 3840 x 2160 since it would likely be way too slow on the Mesa driver.
When booting up an AMD Radeon HD 7950 and NVIDIA GeForce GTX 680 on the system connected to the SE39UY04, the mode was set to 1920 x 1080 and there was no 3840 x 2160 mode exposed. I didn't dig much deeper than that for the Southern Islands and Kepler GPUs on the open-source drivers, since the performance at the 4K Ultra HD resolution would be excessively slow anyways... Especially for the Nouveau driver the performance would be unbearable due to the re-clocking issues. Ultra HD 4K testing on the open-source Linux GPU drivers will happen when the Mesa/Gallium3D drivers are faster and 4K resolutions more common.
When booting up the AMD graphics cards from the HD 7000 series family and newer using the latest Catalyst 13.11 Linux Beta graphics driver, all of them immediately mode-set to the 3840 x 2160 resolution. The mode was set straightaway without having to make any modifications to the AMD settings or the xorg.conf. The only issue to report on the AMD side with the Catalyst Linux driver was small white artifacts appearing on the screen quite often when running at the 4K resolution on Ubuntu.
Lastly, the binary NVIDIA Linux graphics driver was tested with various graphics cards. At first when booting the hardware with the NVIDIA 331.20 Linux graphics driver, mode-setting happened at 1920 x 1080. After doing research, to achieve the 4K resolution for at least the Seiki SE39UY04 Ultra HDTV, the NVIDIA binary driver specific option of -- Option "ModeValidation" "AllowNon60hzmodesDFPModes, NoEDIDDFPMaxSizeCheck, NoVertRefreshCheck, NoHorizSyncCheck, NoDFPNativeResolutionCheck, NoMaxSizeCheck, NoMaxPClkCheck, AllowNonEdidModes, NoEdidMaxPClkCheck" -- needs to be added to the device section of the xorg.conf. It turns out the EDID from the TV is a bit flakey or the NVIDIA binary driver is at least parsing it incorrectly, for which it thinks the EDID checksum and modes are invalid. After adding the ModeValidation options to the xorg.conf and rebooting, mode-setting successfully happened to 3840 x 2160 for all of the tested NVIDIA GeForce "Kepler" graphics cards.