Created attachment 35840 [details]
Example of rendering corruption.

For some time, rxvt-unicode has suffered rendering corruption issues with git
intel driver.  The corruption is most obvious in the Linux menuconfig, so I've
attached a screenshot.  However, there are glitches abound (particularly with
the shell's line editor -- e.g. the cursor doesn't always show up, backspace
does not always cause a character to disappear, etc.), and the terminal
emulator is pretty much impossible to use.

I'm using xserver 1.8.1, libdrm git master, on a T500 laptop with a GM45.

Bisection is a little tricky here because there was an earlier rendering
problem, and the apparent fix for the earlier problem introduced the current
problem.  The earlier problem is that portions of the Linux menuconfig were
rendered in the top left corner of the screen instead of in the terminal
window.  So I ignored the 'rendering in the top left corner' issue and instead
focused on the 'shell line editor glitches' issue and arrived at the following:

524fd2dd0da8f69d4c3f5aebe3a345fe34af609d is the first bad commit
commit 524fd2dd0da8f69d4c3f5aebe3a345fe34af609d
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Sat May 15 18:23:21 2010 +0100

    uxa: Apply clip for solid rectangles.
    
    References:
    
      Bug 28120 - Tint2's tooltip borders end up at 0,0 and do not disappear
      https://bugs.freedesktop.org/show_bug.cgi?id=28120
    
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

:040000 040000 2db3fb330c23e61552addbf9f34bb49679819a6b a93a25ba42ea3dffef678580ca226f2c96cd6bfd M	uxa

git bisect start
# good: [440b4d207b730112169827d0b90b46596659b504] Increase version to 2.11.0
git bisect good 440b4d207b730112169827d0b90b46596659b504
# bad: [9d8ac271404ff219c3d40ae8f829e8b76ac7c359] Merge branch 'glyphs'
git bisect bad 9d8ac271404ff219c3d40ae8f829e8b76ac7c359
# good: [ad8af95dd35921118f45d6cff355c80cf0906ff0] i830: Do not cache in-flight non-reusable buffers.
git bisect good ad8af95dd35921118f45d6cff355c80cf0906ff0
# good: [213816c30b5ca6146e26ded85b2aa31ca16ca9bf] i915: Load texture into directly into OC when possible.
git bisect good 213816c30b5ca6146e26ded85b2aa31ca16ca9bf
# bad: [723cc45b2707aa160eac6d5b56a20e19cc42c8a3] dri: Check error code from GetScratchGC()
git bisect bad 723cc45b2707aa160eac6d5b56a20e19cc42c8a3
# good: [ef95899f5b21453daeabf81a3015b22456d21fec] uxa: Check the w-scaling component is 1 for an translation matrix
git bisect good ef95899f5b21453daeabf81a3015b22456d21fec
# bad: [61835701fd411d3bb550ceee3365e30639e46861] uxa: Patterns are acquired at 0,0
git bisect bad 61835701fd411d3bb550ceee3365e30639e46861
# bad: [524fd2dd0da8f69d4c3f5aebe3a345fe34af609d] uxa: Apply clip for solid rectangles.
git bisect bad 524fd2dd0da8f69d4c3f5aebe3a345fe34af609d
# good: [58b089febceca1e915607bb723ee658aaa9dbed3] uxa: Avoid using blits when with PictFilterConvolution
git bisect good 58b089febceca1e915607bb723ee658aaa9dbed3