Hey there,

I just recently hooked up my old DM800 (first edition) to a 4:3 VGA monitor of mine, and the best resolution I can get working reliably is 576p. 1080i works sometimes, but is stretched as it is assumed to be a 16:9 resolution (understandably), and there doesn't seem to be a way to display it as 4:3 (with letterboxed 16:9).

First off, it's kind of weird that the VGA pins on the DVI-I port output YPbPr instead of RGB, but I have a converter for that, so that's not too bad. What's bad is that the "DVI-PC" modes, which include all the lovely 4:3 resolutions like 1024x768, completely blank the analogue output -- no signal.

The monitor is multisync and has a scan rate of 15-82KHz, 40-120Hz. A mode like 1440x1080@50Hz would be ideal, and at 55.6KHz would be well within range. 960x720@100Hz (76KHz) would be nicer on the eyes, at the expense of some resolution. Since the DM800 caps out at 1080i, I would imagine there to be some limitation in maximum pixel clock. In that case, something like 1280x960@50Hz might be within the realm of possibilities at 83Mhz pixel clock (with 1920x1080@30Hz being 80MHz). Or simply 1440x1080@25Hz (50i).

Is there any way to support modes like these? I looked in /proc/stb/video/videomode_choices, but they're all vague strings like "720p" and have more effects than just the video mode - as mentioned some modes won't output anything over the DVI-A pins, and my guess is that "ntsc" and "pal" only output over SCART.

So in short, is there a more low-level interface to access the framebuffer video modes, or is hacking of source code required? If so, what's the difficulty involved (in other words, is a standard grasp of C/C++ with some knowledge of the generalised timing formula enough)? Or are the available modes a limitation of the Broadcom SoC platform?

Thanks!