Bug 496123

A fairly common issue with multi-head display configurations is that, when you try to arrange monitors side-by-side, it fails due to the framebuffer being too small.

This was commonly the case with the Intel driver up through Fedora 10, as the driver didn't support dynamic framebuffer re-allocation until the Fedora 11 cycle. It now does, so we'll be OK for F11 on that front, but now we have the nouveau driver as the default for NVIDIA chipsets, which does RandR 1.2 (yay) but doesn't do framebuffer reallocation (boo). So it has the exact problem Intel used to have. Try and configure a side-by-side multihead setup out of the box with an NVIDIA adapter on Fedora 11 and it'll almost certainly fail because the available framebuffer size isn't large enough. We had multiple reports of this in the nouveau Test Day, for e.g.

Currently, when hitting this problem, g-d-p either just tries and it doesn't work, or it fails with a cryptic error message. We should improve this behaviour somehow.

I mailed the upstream maintainer, Federico Mena Quintero. He pointed out that Ubuntu has something of a gimcrack solution to this: it's a patch that implements an xorg.conf parser and tries to write an appropriate Virtual line into xorg.conf (this is how you manually specify a big enough framebuffer for a multi-head setup to actually work). We might not necessarily want to have this hack (and besides it probably doesn't work at present if xorg.conf doesn't exist, which is likely to be the case on Fedora), but it's worth evaluating, I guess.

At least, g-d-p should pop up an error dialog with a better explanation of the problem, and possibly a link to a Wiki page or something which explains how to fix it manually.

I'm attaching the Ubuntu patch to be evaluated. (The screen-package.h header it includes basically just does: "gboolean ubuntu_packages_install (GtkWindow *window, const char **packages);")