Nouveau is generally fast but not when it comes to gnome-terminal. Things like opening a new tab, maximizing the window, restoring its size, switching to a desktop with a gnome-terminal on it... take a couple of seconds. The more the window is big, the more it's slow. But it disappears when the gnome-terminal is minimized (reduced in the taskbar). Switching desktops is then instantaneous. The worst is when I maximize it vertically and then open a new tab. X seems like frozen, thought I can still move the mouse but clicking has no effect. It doesn't happen with xterm, so I guess gnome-terminal is using rendering paths that are not accelerated in nouveau. The card is a 8400M GS plugged to a 1280x800 LVDS, without any external screen. As accidentally discovered with bug #20065, it doesn't happen in ShadowFB NoAccel mode. I'm quite puzzled about what information I could give you now. Or maybe the bug is know and this bug will remain open until it's fixed. Regards
For some reason gnome-terminal is trying to composite from the frontbuffer (use it as a source). We (nouveau, nv50+) don't know how to tile the frontbuffer, and the 3d engine cannot sample from a linear texture. So that causes a fallback and a pretty ugly one it seems.
How is this coming along? Any more info or testing needed?
This is fixed now. Just be using a recent X server (1.7 or 1.7 pre-releases), and git of all the nouveau bits and you'll be fine.
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.