Bug 96298

Summary:	32-bit failures for spec.arb_compute_shader.execution.atomic-counter
Product:	Mesa	Reporter:	Mark Janes <mark.a.janes>
Component:	Drivers/DRI/i965	Assignee:	Jordan Justen <jljusten>
Status:	RESOLVED DUPLICATE	QA Contact:	Intel 3D Bugs Mailing List <intel-3d-bugs>
Severity:	normal
Priority:	medium	CC:	currojerez
Version:	git
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Mark Janes 2016-05-31 21:39:36 UTC

with mesa 357495b94dad4101a5491ed30782574162de58db, this test was enabled, and found to be failing *only* on 32 bit platforms.

This could indicate a bug in mesa or a bug in the test.

/tmp/build_root/m32/lib/piglit/bin/shader_runner /tmp/build_root/m32/lib/piglit/tests/spec/arb_compute_shader/execution/atomic-counter.shader_test -auto
piglit: debug: Requested an OpenGL 3.2 Core Context, and received a matching 4.2 context

Atomic counter 1 test failed: Reference == Observed
  Reference: 2147483647
  Observed:  4294966784

It is notable that the reference value is 7FFFFFFF, which may indicate an 32-bit overflow error.

Jordan, can you verify that the test is correct for 32 bit platforms?

Comment 1 Jordan Justen 2016-05-31 22:13:59 UTC

tests/spec/arb_compute_shader/execution/atomic-counter.shader_test

uses atomic_uint, which should be a 32-bit value on 64-bit processes
as well. The test has a uint atomic counter that starts at 0, and gets
decremented 512 times.

Does this test have a similar failure?
tests/spec/arb_shader_atomic_counters/execution/atomic-counter.shader_test

https://www.opengl.org/registry/specs/ARB/shader_atomic_counters.txt
says "Increments and decrements at the limit of the range will wrap
to [0, 2^32-1]", so I think the test is valid. The shader_runner
code looks valid for treating the buffer as a uint32_t pointer.

Comment 2 Mark Janes 2016-05-31 22:41:33 UTC

I don't see any failures from that shader test.

Comment 3 Jordan Justen 2016-05-31 23:12:36 UTC

Sorry. I guess that was a test that I made when adding shader_runner
atomic counter support, but I didn't send it to piglit.

I added it in my freedesktop.org piglit repo atomic-fs branch.

Comment 4 Mark Janes 2016-06-03 22:36:47 UTC


*** This bug has been marked as a duplicate of bug 93333 ***

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