Bug 49668

This was an expected regression.  As the commit message indicates, the patch intentionally causes incorrect rendering in order to avoid a GPU hangs (which would be much worse).  The test is failing because of the intentional incorrect rendering.

The incorrect rendering only happens in a rare use case (mipmapped depth and stencil textures), and it only happens when the texture alignment is poor (which should only happen for non-power-of-two surfaces, and for the tiniest miplevels of a power-of-two surface), so the incorrect rendering is very unlikely to cause actual problems for users.  A lot of work would be required to get correct rendering and avoid GPU hangs, so we've decided not to address this bug further unless it causes a problem in a real-world application.

Accordingly, I'm adjusting the importance of this bug to low/minor.  If we find a real-world application that doesn't render correctly because of this bug, we can escalate.

*** Bug 53522 has been marked as a duplicate of this bug. ***

this is caused by https://bugs.freedesktop.org/show_bug.cgi?id=50271

fbo-depth-array now passes on my IVB system.

Fixed on ivybridge with mesa master branch.

It still happens on mesa 9.0 branch.

fbo/fbo-depth-array still fails on sandybridge, Ironlake with master branch..
output:
[root@x-pk2 bin]# ./fbo-depth-array -auto
WARNING: Depth/stencil buffer needs alignment to 8-pixel boundaries.
Truncating offset, bad rendering may occur.
Probe at (34,27)
  Expected: 0.200000 0.200000 0.200000
  Observed: 0.000000 0.000000 0.000000
Probe at (67,29)
  Expected: 0.400000 0.400000 0.400000
  Observed: 0.000000 0.000000 0.000000
Probe at (100,31)
  Expected: 0.600000 0.600000 0.600000
  Observed: 0.000000 0.000000 0.000000
Probe at (166,27)
  Expected: 1.000000 1.000000 1.000000
  Observed: 0.000000 0.000000 0.000000
PIGLIT: {'result': 'fail' }

Following cases fixed on sandybridge, ivybridge and ironlake with mesa master branch:
spec_ARB_depth_buffer_float_fbo-clear-formats
spec_ARB_depth_texture_fbo-clear-formats
spec_EXT_packed_depth_stencil_fbo-clear-formats

Do we have any idea which commit(s) on master fixed the problem? Are these candidates to pick to 9.0?

Fixed on master branch by commit 7139ab80ca9b1b3572ef6da98765ca783e8e5e3b(except fbo/fbo-depth-array).
commit 7139ab80ca9b1b3572ef6da98765ca783e8e5e3b
Author: Eric Anholt <eric@anholt.net>
Date:   Wed Aug 8 09:03:26 2012 -0700

    i965: Fix rendering to small mipmaps of depth/stencil buffers using a temp mt.

    Fixes 51 piglit tests (fbo-clear-formats, and most of the remaining failures
    in depthstencil).


fbo/fbo-depth-array fixed on Ivybridge by commit 9f0f2f9512c3c9dcf875efa490b587f010b260c1.
commit 9f0f2f9512c3c9dcf875efa490b587f010b260c1
Author: Marek Olšák <maraeo@gmail.com>
Date:   Mon Jul 2 17:10:09 2012 +0200

    mesa: use FLUSH_CURRENT and not FLUSH_VERTICES in _mesa_validate_*

    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH_WITH_RETVAL calls FLUSH_VERTICES, which
    is not what we want.

    This fixes a breakage in classic drivers, introduced in:

      62b971673950148eb949ba23d7fdc47debea16f0
      vbo: first ASSERT_OUTSIDE_BEGIN_END then FLUSH, not the other way around

    It should fix:
      https://bugs.freedesktop.org/show_bug.cgi?id=51629
      https://bugs.freedesktop.org/show_bug.cgi?id=51642

fbo/fbo-depth-array still fails on sandybridge and ironlake.

No, they're way too invasive.

Still fails on sandybridge and ironlake.
output:
WARNING: Depth/stencil buffer needs alignment to 8-pixel boundaries.
Truncating offset, bad rendering may occur.
Probe at (34,1)
  Expected: 0.200000 0.200000 0.200000
  Observed: 0.298039 0.298039 0.298039
Probe at (100,1)
  Expected: 0.600000 0.600000 0.600000
  Observed: 0.098039 0.098039 0.098039
Probe at (166,1)
  Expected: 1.000000 1.000000 1.000000
  Observed: 0.501961 0.501961 0.501961
PIGLIT: {'result': 'fail' }

I can't reproduce it with latest mesa upstream (commit commit 0c0ca557117edd3a57443f4f454c3a8da1d4e0b5)

Make sure to keep intel-3d-bugs@ in the email list.

Test on the latest Mesa master branch, it works well.
output:
Testing 32x32x6
PIGLIT: {"result": "pass" }

Verified.Fixed.