This bug shows when overlaying windows are moved accross each other, most notably with xpdf and applications using the athena widget system. The symptoms are incorrect rendering and damaged graphics in the regions damaged by moving the window. This bug is a duplicate of 30528, where, specifically, it has been reported as "unredrawn borders". This bug persists in release 2.15.0 of the intel driver, but unlike the previous reports, this one includes a patch fixing the problem. The bug is in uxa/accel.c, around lines 180ff, in uxa_fill_spans() where a test whether the line to be drawn is in the damaged region is incorrect. while (nbox--) { if (pbox->y1 > fullY1) break; if (pbox->y1 <= fullY1 && pbox->y2 > fullY1 /* bug was here!!!*/ ) { partX1 = pbox->x1; if (partX1 < fullX1) partX1 = fullX1; partX2 = pbox->x2; if (partX2 > fullX2) partX2 = fullX2; The test for "pbox->y2 > fullY1" was missing here in the marked line.
Your patch definitely looks correct to me, though it doesn't fix the corruption I see when dragging a gnome-terminal over an xpdf or nedit window under metacity (particularly in the metacity window decorations, though bits of junk also show up in the window contents). Care to submit a full patch using git format-patch so we can make sure we get the attribution right on your change?
Scratch that, my testing was just bad. And, on second thought, I want to delete a bunch of this clipping code since it's way overcomplicated, but getting your simple fix in would still be good because it means we could cherry-pick it back to previous releases.
Went ahead and pushed the code deletion as-is: commit e0066e77e026b0dd0daa0c3765473c7d63aa6753 Author: Eric Anholt <eric@anholt.net> Date: Tue May 31 23:17:16 2011 -0700 uxa: Simplify Composite solid acceleration for spans by only clipping once. Unlike the previous commit removing this style of code, the code in this one was originally wrong, and would fail to clip in the second pass of clipping when y was > pbox->y2. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=37233 Reviewed-by: Keith Packard <keithp@keithp.com>
Created attachment 49782 [details] screen shot of libreoffice --calc Hello, bisecting blames this commit for a curious graphic glitch at a ThinkPad T400 (integrated intel GM45 graphic) - seen in the attached screen shot. When I start libeoffice (--calc) and close the empty sheet, few portion of the windows still shows the content of the sheet. This is harmless in the given example but might be more than only annoying for sensitive content : e0066e77e026b0dd0daa0c3765473c7d63aa6753 is the first bad commit
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