[Intel-gfx] [PATCH] drm/i915/selftests: Ensure we don't clamp a random offset to 32b

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> Quoting Mika Kuoppala (2019-07-10 16:34:23)
>> Chris Wilson <chris at chris-wilson.co.uk> writes:
>> 
>> > Specify that we do want a 64b value for sizeof(u32) as we want to
>> > compute the mask of the upper 62bits.
>> >
>> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> > Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
>> > index 3abe15a08b6d..275ec1bfc2be 100644
>> > --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
>> > +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
>> > @@ -1539,7 +1539,7 @@ static int igt_vm_isolation(void *arg)
>> >  
>> >                       div64_u64_rem(i915_prandom_u64_state(&prng),
>> >                                     vm_total, &offset);
>> > -                     offset &= -sizeof(u32);
>> > +                     offset &= -(u64)sizeof(u32);
>> 
>> Taking a sizeof of something we know the size of.
>
> u32 is a proxy for dword, and I was just trying to be more expressive
> that we want the address aligned to a dword for the MI_STORE_DWORD_IMM
> used. alignof_dword maybe?

I was being a bit snarky. It is more expressive than -4 indeed.
Compromise as we dont have a define for natural aligment for
command streamer memory access.

-Mika