https://bugs.freedesktop.org/show_bug.cgi?id=33867 --- Comment #9 from Mario Kleiner <mario.kleiner@xxxxxxxxxxxxxxxx> 2011-02-05 14:15:29 PST --- Looking at your description and the "look-alike bug" youtube video, i wonder if it could be some synchronization bug in mesa, the ddx or a running desktop compositor instead of a kernel bug. Something for which pageflipping is a neccessary condition to show up. This... <https://www.crowproductions.de/repos/prboom/branches/prboom-plus-24/prboom2/src/gl_wipe.c> ...i believe is the code responsible for the wipe effect which goes wrong. They take a screenshot of the start screen before the transition into a texture and another screenshot of the end screen after the transition. Then they go through a loop were they draw textured quads, first the fullscreen start-screen texture, then little stripes with bits of the end screen texture. If the wipe_scr_start_tex texture would contain all-black, you'd get the visual artifacts you describe. That could be because they are capturing an all-black framebuffer instead of the proper one, e.g., because mesa fails to synchronize its framebuffer readback into textures properly with the pageflip, or because it reads from the wrong buffer (pre-pageflip vs. post-pageflip). Without pageflipping (enabled), there isn't any buffer exchange between front- and backbuffer, so a possible bug in mesa would probably stay hidden. I do remember that we had to fix some such bugs in the mesa classic driver, also for the framebuffer readback path, i don't know about the status of the gallium version. You could disable page-flipping via the xorg.conf option "EnablePageFlip" "off" (iirc) and see if that "fixes" the problem without removing any patches. Or if disabling desktop composition makes a difference. One could also mess with that file to see if something changes. E.g., adding a glFlush() or glFinish() or some wait for a few hundred msecs before executing the screenshot makes a difference. Or just display the screenshot texture for a few seconds to see if it is indeed a black texture. -mario -- Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
