In principle, this sounds reasonable. Modular construction breaks through a lot of bottlenecks. However, not all machines have PCIe slots. My newest one has AGP; the rest have only PCI. How hard would it be to offer the same frame buffer and analog back end on more than one base board?
We might find that the cost of DACs and cable drivers explodes above 2560x1600, if available at all. Better connectors and cables might also be required at such high pixel rates; it might even be necessary to move the DACs off the board and onto a plug mounted on the monitor itself to avoid physical problems in signal transmission. But nothing says there has to be only one model of OGC base board. If the GPU is conceived as a piggyback board, rather than a socketed IC, the base board would be a lot more future-proof. The important thing is to select a board-to-board connector pair that can support very fast digital signals, probably as LVDS. One thing I'd like to see is a jumper header or DIP switch that can lock it into any of the oldest and most generic VGA modes and block all software mode commands, for bootstrapping a system up from bare iron with a generic monitor. That would also be good for debugging drivers and config files. One possible use for the socket would be a fixed-frequency jumper plug module in place of the GPU Jack Carroll ----- Original Message ----- From: "Dieter BSD" <[email protected]> To: [email protected] Sent: Friday, December 7, 2012 8:15:42 PM Subject: [Open-graphics] Open Framebuffer board Here is a summary of what I think we want in an open framebuffer board: PCIe Number of lanes to be determined At least 2 heads How much would extra heads increase price? I think 3 heads should cover most users' needs. At least 2560x1600 Is 4096*2160 unreasonable? At least 24 bit color Support for VGA, component, s-video, composite (others?) Support for DVI, HDMI, Displayport (others?) Support for use as console Support for adding an optional OGP-GPU (Open Graphics Project GPU): Option 1) Socket for FPGA / DSP / other? use the same pinout for OGP-GPU chip Option 2) a mini-PCIe slot or 2 put OGP-GPU on mini-PCIe card (allows adding an optional Broadcom Crystal HD video decoder, or any other Mini-PCIe card) Option 2 is probably less expensive. Would it create a bottleneck or other problem? Bracket connectors: Option 1) DVI, s-video, HDMI, and (mini?) Displayport (if they all fit) Option 2) LFH connector(s) [1] plus breakout cables Option 2 might allow having any combination of ports the user needs, without adapters to convert one type of port to another. It isn't always possible to convert a port to the type needed. This would require the output drivers to have sufficient versatility. Is this doable, oh analog gurus? There are existing video cards that use LFH connectors, so it might be possible to use the existing off-the-shelf breakout cables. [1] http://en.wikipedia.org/wiki/Low-force_helix People that don't need a gpu can immediately use the board as is. Once the OGP-GPU is available, users that want/need a gpu can just plug it in. Depending on what socket(s)/slot(s) we include, users can add FPGA, DSP, video decoder, etc. Some of these parts may not be as open as we would like, but they are optional. It should be possible for the board itself to be completely documented. The idea is that we only need to design and build one board that is versatile enough to serve a wide range of uses, and to remain useful for a long time. (That's why I'm hoping we can support 4K displays. 4K displays are rare and expensive today, but are likely to become less expensive, as consumer electronics usually does.) And it should be possible to keep the card relatively inexpensive. I'm sure that price was a major reason that there wasn't a lot of demand for the OGD1. The power consumption should be quite low. No extra power cables, no "jet engine" fans, no heatsinks. So, who can fill in some of the details that I'm not sure about? Have I left out anything? _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com) _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
