Created attachment 35858 [details] [review]
glxgears: Add option to enable override redirect.

Displaying an OpenGL window which is wider than the current framebuffer results
in graphical corruption and/or a GPU hang.  I have even seen the screen's DPI
setting magically change as a result, suggesting some more insidious memory
corruption is at play.

To make things more interesting, the issue only occurs if the OpenGL window is
the only thing visible on the entire screen.  For example, to reproduce on a
1680x1050 laptop screen, I run glxgears -geometry 2000x1500 (which works fine),
then reposition the window so that the OpenGL area extends beyond all four
sides of the screen (still working fine) and finally set the window's layer to
be above all other windows (including my panels), at which point the corruption
occurs immediately.

I have attached a patch for glxgears (against mesa/demos.git) which allows one
to enable override_redirect on the window, making it much easier to reproduce
without any window manager intervention: on a 1680x1050 screen, simply run
glxgears -override -geometry 2000x1500 and boom!

I'm using a T500 laptop with a GM45, xserver 1.8.1, git libdrm, git mesa.  Also occurs with mesa 7.8.1.

This is a regression from xf86-video-intel-2.10.0.  Bisection results follow.

1a76fa5574e8e8f88ac3518a4e4494e1af301dc1 is the first bad commit
commit 1a76fa5574e8e8f88ac3518a4e4494e1af301dc1
Author: Keith Packard <keithp@keithp.com>
Date:   Fri Jan 29 23:28:46 2010 -0800

    Initialize DRI2 info rec version 4 list of driver names

    With DRI2 supporting multiple subsystems, the video driver must
    initialize the list of driver names instead of just passing the single
    driver name used by Mesa. Without this, the X server will fail to
    initialize DRI2 as the numDrivers field in this structure will be
    uninitialized.

    Signed-off-by: Keith Packard <keithp@keithp.com>

:040000 040000 649cf372a1096de98cea5bb6f5df159d5b8159d5 49c76ac6b97ed5d3678fbeca3ec5961500bcb9d4 M      src

git bisect start
# bad: [b645ec83e0d86f2247b8338ceab60b9502516e70] uxa: Apply the drawable offset to the solid rects
git bisect bad b645ec83e0d86f2247b8338ceab60b9502516e70
# good: [091035146463bf1aa6674bff6947d04fc620c18f] configure.ac: Bump version to 2.10.0.
git bisect good 091035146463bf1aa6674bff6947d04fc620c18f
# bad: [90a971c60769781f53827b469a9be3aab14cf71c] uxa: Only reduce a composite to a BLT if it is wholly contained
git bisect bad 90a971c60769781f53827b469a9be3aab14cf71c
# bad: [086c0e25cac1d3dd0a37def8b5cb82c1c6279edf] i830_memory: rename i830_bind_all_memory to reflect code reality
git bisect bad 086c0e25cac1d3dd0a37def8b5cb82c1c6279edf
# bad: [a86869e6c3131b83a2ad529bc313270a9f45f5bd] Fix an unused variable warning for !INTEL_XVMC.
git bisect bad a86869e6c3131b83a2ad529bc313270a9f45f5bd
# good: [93cd943d41c646c794b8cb5a960d8f0805e15395] intel: Use the compositing-aware colorkey filler instead of homebrew fail.
git bisect good 93cd943d41c646c794b8cb5a960d8f0805e15395
# bad: [6610bcbac51c9ac970128012f0d4566d8cfba000] DRI2: only use version 4 APIs if kernel support exists
git bisect bad 6610bcbac51c9ac970128012f0d4566d8cfba000
# good: [5f93d019dc6311dd16b6792ffb60dbfc45ef3d08] uxa: Adjust uxa_get_color_for_pixmap to match prototype
git bisect good 5f93d019dc6311dd16b6792ffb60dbfc45ef3d08
# good: [918151a7955c26174db80b775205f6ffb4f44ab6] uxa: Fix compatible_formats() for OVER
git bisect good 918151a7955c26174db80b775205f6ffb4f44ab6
# bad: [1a76fa5574e8e8f88ac3518a4e4494e1af301dc1] Initialize DRI2 info rec version 4 list of driver names
git bisect bad 1a76fa5574e8e8f88ac3518a4e4494e1af301dc1