Max 3D frame buffer size causes corrupted, unusable display
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| Compiz Core |
Expired
|
Undecided
|
Unassigned | ||
| compiz (Ubuntu) |
Expired
|
Undecided
|
Unassigned | ||
Bug Description
Binary package hint: compiz
This is similar to Bug #745839 (for a while I thought that's what it was), but not quite the same issue. Compiz renders everything to a single, giant OpenGL window that covers the entire display area. If your display area is larger than your video card's maximum *framebuffer* size (not *texture* size as in Bug #745839), OpenGL fails to initialize.
Compiz does not detect this failure, and so still covers your screen with this window which now does not have an OpenGL context bound to it. As a result, all drawing operations fail. The window never gets redrawn, so it keeps displaying whatever happened to be in the block of video memory allocated to it (which in my case is usually a corrupted version of the desktop wallpaper). The apparent effect is that all you can see is a screenfull of garbage; the cursor still changes and interacts with windows, but they aren't visible.
This problem isn't solved by breaking windows into multiple small textures, since the issue isn't the size of the window textures but the size of the OpenGL framebuffer they're being drawn into. The only workaround I can think of would be to create multiple OpenGL windows (probably one per monitor) and split the drawing between them. (Hopefully it's possible to share textures between multiple OpenGL windows; otherwise it might be necessary to forbid a window from ever spanning across multiple screens.)
This issue is the cause of the error message: r300: Implementation error: Render targets are too big in r300_set_
The same can be seen with other programs, e.g.: glxgears --geometry 3000x1000+0+0
This displays the same error message and the same window full of garbage (at least for one frame before glxgears resizes its window for some reason).
Since the corrupted display is really just a window covering everything, it's still possible to kill Compiz (by blindly clicking or typing or using another terminal) and get the display working again, but for novice users the apparent effect would be that they simply can't see any windows.
| description: | updated |
| jhfhlkjlj (fdsuufijjejejejej-deactivatedaccount) wrote | #1 |
| Changed in compiz (Ubuntu): | |
| status: | New → Incomplete |
| Changed in compiz-core: | |
| status: | New → Incomplete |
| Launchpad Janitor (janitor) wrote | #2 |
| Changed in compiz (Ubuntu): | |
| status: | Incomplete → Expired |
| Launchpad Janitor (janitor) wrote | #3 |
| Changed in compiz-core: | |
| status: | Incomplete → Expired |
Thank you for taking the time to report this bug and helping to make Ubuntu better. We are sorry that we do not always have the capacity to look at all reported bugs in a timely manner. There have been many changes in Ubuntu since that time you reported the bug and your problem may have been fixed with some of the updates. Compiz, in particular, is in heavy development and this bug may have been fixed in the development version of Ubuntu (12.04) if not on your current version. If you are able, it would be of great help if you could confirm if the bug still exists by testing a livecd (available at ubuntu.com). When you test it and it is still an issue, kindly upload the updated logs by running apport-collect <bug #> and any other logs that are relevant for this particular issue. If you are unable to test the development version, please let us know if you are able to reproduce this issue on Ubuntu 11.10.
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