ok , using this workaround I can change resolution mode, but setting a resolution D:1366x768p-59 efika output is 1366x768 H:49.4KHz V:62Hz so my Philips 191v (pc monitor) show output but Monitor TV Philips 32" show black screen and alert 'out of range' (monitor is native 1366x768 and max V frequency is 60Hz!).
The modes are pulled from EDID so you can't just set it to that mode and hope it works somewhere else (1366x768p-59 or 1366x768p-60 is misleading, these are modes with that resolution and refresh, but the timings are not included in the name so in actual fact if you see those strings on ANY other monitor they are probably NOT going to work!)
Later, unreleased (since we introduced a smattering of bugs which we are still fixing) kernels do have a siihdmi.vic=N argument which allows you to pick a CEA video mode for true HDMI displays (so if there are some vast number of normal TV modes to choose from you can force the issue. =1 is 640x480, =4 is 720p60, blah blah, you can look it up online pretty easily what the VIC code is for most modes, but it MUST be present in the EDID for the monitor for it to work).
What's missing truly, truly is XRandR support, but it's really difficult to actually get working since XRandR relies on the EDID being processed in the Xorg driver too, which means porting all the filtering to userspace and matching it when we find bugs. You may have a boot mode that works but XRandR lets you pick a subtle different mode that doesn't and you get a dead screen, that is not fun and not what we want users to experience.
I am afraid to say you probably won't see XRandR support to go with the 2.6.31 kernel just because of that. However work is progressing on a 3.4 kernel release which, although we are not really supporting MX51 anymore, should solve a lot of problems in this regard (since it's a DRM display driver) and increase performance.
Matt Sealey, Genesi USA Inc.
Product Development Analyst