[igt-dev] [PATCH i-g-t] tests/prime_vgem: Skip basic-read/write subtests if no mappable GGTT

[Janusz Krzysztofik]

On Wednesday, November 20, 2019 4:53:30 PM CET Chris Wilson wrote:
> Quoting Janusz Krzysztofik (2019-11-20 15:49:33)
> > (fixing malformed intel-gfx list address in Cc:)
> > 
> > On Wednesday, November 20, 2019 4:36:41 PM CET Chris Wilson wrote:
> > > Quoting Janusz Krzysztofik (2019-11-20 15:32:19)
> > > > As we've agreed that using I915_GEM_PREAD/PWRITE IOCTLs on dma-buf
> > > > objects doesn't make much sense, we are not going to extend their
> > > > handlers in the i915 driver with new processing paths required for them
> > > > to work correctly with dma-buf objects on future hardware with no
> > > > mappable aperture.  When running on that kind of hardware, just skip
> > > > subtests which use those IOCTLs.
> > > > 
> > > > Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
> > > > Cc: Daniel Vetter <daniel at ffwll.ch>
> > > > Cc: Joonas Lahtinen <joonas.lahtinen at intel.com>
> > > > ---
> > > >  tests/prime_vgem.c | 6 ++++++
> > > >  1 file changed, 6 insertions(+)
> > > > 
> > > > diff --git a/tests/prime_vgem.c b/tests/prime_vgem.c
> > > > index 2b21ff41..b7bbd989 100644
> > > > --- a/tests/prime_vgem.c
> > > > +++ b/tests/prime_vgem.c
> > > > @@ -37,6 +37,8 @@ static void test_read(int vgem, int i915)
> > > >         uint32_t *ptr;
> > > >         int dmabuf, i;
> > > >  
> > > > +       gem_require_mappable_ggtt(i915);
> > > 
> > > If that were the case, the change in ABI would not be tied to the mmap
> > > ABI.
> > 
> > SInce dma-buf objects have no stuct page, the pwrite ioctl handler tries to 
> > use i915_gem_gtt_pwrite_fast().  There, both i915_gem_object_ggtt_pin() and 
> > insert_mappable_node() fail.  Isn't that because of missing mappable aperture?
> 
> But the query you make would be "what is the pwrite/pread ABI"? And we
> want that to tick independently of other ioctls.

OK, now it's clear for me, I hope.

Thanks,
Janusz

> -Chris
>