I've spent all of my lab time since discovering the bug mention in my last post trying to resolve it. I've tried all of the interesting Nvidia xorg.conf settings, all of the interesting settings from their config tool, several Xgl settings, and turning on Twinview. I haven't tried *permutations* of all these yet (ich), but I don't think it would help since I have observed no difference in Xgl's behavior. I am good at reproducing the bug, however.
Of course spending the last 30 hours troubleshooting it is time away from the plugin. I *need* to be able to run Compiz across all the video outputs for display correction to work as I've written it so far. Anything else would be a bit of an architecture shift.
Therefore, I'm suggesting we perhaps return the 9800 GTs I picked up and order a couple of these to run with one of Renau's cards.
It is a box that will split a single vga or dvi input into 3 dvi outputs. It does whatever hardware magic needs to happen to simple present one high-resolution screen to the PC. With two of them, we could drive 6 projectors from one videocard using one framebuffer which avoids the problem I'm having now.
The downside is the price: $600. On the other hand, we are doing OK on our budget right? And I did drop $120 x 3 on videocards this weekend so it isn't too extreme. Also, the whole setup tops out at 6 projectors I think.. unless we can daisy chain them..
The upside is that display correction will work and it liberates our software stack a lot. Using one card, there is no longer a dependency on Xinerama and therefore on Xgl and therefore on an older X server. Not using Xgl yields better performances, as does not using Xinerama -- graphics data does not have to be copied between cards. Not having to run an older X server lets us run with newer distros, and even better, with MPX.
Obviously it is a bit late now to realize all of those improvements. Just getting display correction working will be enough for now.
I remember talking about the triplehead2go boxes near the beginning of the quarter, and we did balk at them being pricy. I think more of what happened though is that I became focused on a certain approach because of the cards Renau gave us initially, and I did not realize when I stopped using the cards that the design could change in this way. There is probably some Ideo design pattern I should have been remembering in order to avoid that trap.
10 years ago