[Piglit] [PATCH 2/2] arb_shader_image_load_store/invalid: Skip the index bounds test on Intel Ivybridge hardware.

[Jordan Justen]

I don't know of any other cases where we skip a test based on the
render name. I don't think this is a good practice to start.

-Jordan

On 2015-07-24 11:01:47, Francisco Jerez wrote:
> This test is known to cause a GPU hang on IVB due to a hardware bug.
> The reason is that the hardware seems to be unable to cope with
> binding table indices mapping to an invalid surface, which is
> sometimes the case when a shader accesses an array of images out of
> bounds.
> 
> According to the ARB_shader_image_load_store spec "if the index used
> to select an individual element [of an array of images] is negative or
> greater than or equal to the size of the array, the results of the
> operation are undefined but may not lead to termination." -- Which is
> precisely one of the typical outcomes of the GPU hang caused by this
> test.
> 
> In theory this could be fixed by implementing array bounds checking in
> software, but it doesn't seem worth doing because on the one hand it
> would punish well-behaved applications unnecessarily, and on the other
> hand there doesn't seem to be any reasonable use-case for the
> behaviour required by the spec [the implementation may set the
> computer on fire as long as it somehow manages not to terminate the
> program ;)].
> 
> If the breakage caused by this test case was confined to a single
> process I would probably consider to leave it alone, however I've
> noticed that in some cases the hang will cause other unrelated piglit
> tests that happen to be run in parallel to fail, causing some random
> noise in the results we get from our piglit system, what makes them
> rather difficult to interpret.
> ---
>  tests/spec/arb_shader_image_load_store/invalid.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/tests/spec/arb_shader_image_load_store/invalid.c b/tests/spec/arb_shader_image_load_store/invalid.c
> index a0981e4..52b3275 100644
> --- a/tests/spec/arb_shader_image_load_store/invalid.c
> +++ b/tests/spec/arb_shader_image_load_store/invalid.c
> @@ -292,6 +292,17 @@ invalidate_address_bounds(const struct image_info img, GLuint prog)
>  }
>  
>  static bool
> +can_test_index_bounds(void)
> +{
> +   /* This test is known to cause a GPU hang on Intel Ivybridge
> +    * hardware due to a hardware bug.  Don't annoy users
> +    * unnecessarily.
> +    */
> +   return !strstr((const char *)glGetString(GL_RENDERER),
> +                  "Intel(R) Ivybridge");
> +}
> +
> +static bool
>  invalidate_index_bounds(const struct image_info img, GLuint prog)
>  {
>          return set_uniform_int(prog, "u", 0xdeadcafe);
> @@ -444,7 +455,7 @@ piglit_init(int argc, char **argv)
>                   *  element is negative or greater than or equal to
>                   *  the size of the array [...]"
>                   */
> -                subtest(&status, true,
> +                subtest(&status, can_test_index_bounds(),
>                          run_test(op, def_img, def_img,
>                                   invalidate_index_bounds, true),
>                          "%s/index bounds test", op->name);
> -- 
> 2.4.3
> 
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