Re: [PATCH v3 5/8] drm/i915/selftests: Add live vma selftest

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Sep 25, 2018 at 09:40:30PM +0100, Chris Wilson wrote:
> Quoting Ville Syrjala (2018-09-25 20:37:11)
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Add a live selftest to excercise rotated/remapped vmas. We simply
> > write through the rotated/remapped vma, and confirm that the data
> > appears in the right page when read through the normal vma.
> > 
> > Not sure what the fallout of making all rotated/remapped vmas
> > mappable/fenceable would be, hence I just hacked it in the test.
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  .../gpu/drm/i915/selftests/i915_live_selftests.h   |   1 +
> >  drivers/gpu/drm/i915/selftests/i915_vma.c          | 136 +++++++++++++++++++++
> >  2 files changed, 137 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/selftests/i915_live_selftests.h b/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
> > index a15713cae3b3..095e25e92a36 100644
> > --- a/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
> > +++ b/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
> > @@ -15,6 +15,7 @@ selftest(workarounds, intel_workarounds_live_selftests)
> >  selftest(requests, i915_request_live_selftests)
> >  selftest(objects, i915_gem_object_live_selftests)
> >  selftest(dmabuf, i915_gem_dmabuf_live_selftests)
> > +selftest(vma, i915_vma_live_selftests)
> >  selftest(coherency, i915_gem_coherency_live_selftests)
> >  selftest(gtt, i915_gem_gtt_live_selftests)
> >  selftest(gem, i915_gem_live_selftests)
> > diff --git a/drivers/gpu/drm/i915/selftests/i915_vma.c b/drivers/gpu/drm/i915/selftests/i915_vma.c
> > index 6e84e5cc93a0..e0e4d4578c4d 100644
> > --- a/drivers/gpu/drm/i915/selftests/i915_vma.c
> > +++ b/drivers/gpu/drm/i915/selftests/i915_vma.c
> > @@ -797,3 +797,139 @@ int i915_vma_mock_selftests(void)
> >         return err;
> >  }
> >  
> > +static int igt_vma_remapped_gtt(void *arg)
> > +{
> > +       struct drm_i915_private *i915 = arg;
> > +       const struct intel_remapped_plane_info planes[] = {
> > +               { .width = 1, .height = 1, .stride = 1 },
> > +               { .width = 2, .height = 2, .stride = 2 },
> > +               { .width = 4, .height = 4, .stride = 4 },
> > +               { .width = 8, .height = 8, .stride = 8 },
> > +
> > +               { .width = 3, .height = 5, .stride = 3 },
> > +               { .width = 3, .height = 5, .stride = 4 },
> > +               { .width = 3, .height = 5, .stride = 5 },
> > +
> > +               { .width = 5, .height = 3, .stride = 5 },
> > +               { .width = 5, .height = 3, .stride = 7 },
> > +               { .width = 5, .height = 3, .stride = 9 },
> > +
> > +               { .width = 4, .height = 6, .stride = 6 },
> > +               { .width = 6, .height = 4, .stride = 6 },
> > +               { }
> > +       }, *p;
> > +       enum i915_ggtt_view_type types[] = {
> > +               I915_GGTT_VIEW_ROTATED,
> > +               I915_GGTT_VIEW_REMAPPED,
> > +               0,
> > +       }, *t;
> > +       struct drm_i915_gem_object *obj;
> > +       int err = 0;
> > +
> > +       obj = i915_gem_object_create_internal(i915, 10 * 10 * PAGE_SIZE);
> > +       if (IS_ERR(obj))
> > +               return PTR_ERR(obj);
> > +
> > +       mutex_lock(&i915->drm.struct_mutex);
> > +
> > +       for (t = types; *t; t++) {
> > +               for (p = planes; p->width; p++) {
> > +                       struct i915_ggtt_view view = {
> > +                               .type = *t,
> > +                               .rotated.plane[0] = *p,
> > +                       };
> > +                       struct i915_vma *vma;
> > +                       u32 __iomem *map;
> > +                       unsigned int x, y;
> > +                       int err;
> > +
> > +                       err = i915_gem_object_set_to_gtt_domain(obj, true);
> > +                       if (err)
> > +                               goto out;
> > +
> > +                       vma = i915_gem_object_ggtt_pin(obj, &view, 0, 0, PIN_MAPPABLE);
> 
> Ok. Code needs a little more help to allow PIN_MAPPABLE on unfenceable
> vma. Personally, I'd just kill the exception from
> __i915_vma_set_map_and_fenceable(). Nobody actually grabs the fence for
> remapped vma afaict, so we shouldn't end with a wasted fence.

I think intel_pin_and_fence_fb_obj() would grab one. It just checks for
i915_vma_is_map_and_fenceable() currently. But we can easily avoid that
by having intel_plane_uses_fence() return false for remapped/rotated
vma.

> 
> > +                       if (IS_ERR(vma)) {
> > +                               err = PTR_ERR(vma);
> > +                               goto out;
> > +                       }
> 
> Hmm, I guess we might need a GEM_BUG_ON(vma->view.type != *t); and co
> 
> > +
> > +                       /* kludge */
> > +                       vma->flags |= I915_VMA_CAN_FENCE;
> > +
> > +                       map = i915_vma_pin_iomap(vma);
> > +                       i915_vma_unpin(vma);
> > +                       if (IS_ERR(map)) {
> > +                               err = PTR_ERR(map);
> > +                               goto out;
> > +                       }
> > +
> > +                       for (y = 0 ; y < p->height; y++) {
> > +                               for (x = 0 ; x < p->width; x++) {
> > +                                       unsigned int offset;
> > +                                       u32 val = y << 16 | x;
> > +
> > +                                       if (*t == I915_GGTT_VIEW_ROTATED)
> > +                                               offset = (x * p->height + y) * PAGE_SIZE;
> > +                                       else
> > +                                               offset = (y * p->width + x) * PAGE_SIZE;
> > +
> > +                                       iowrite32(val, &map[offset / sizeof(*map)]);
> > +                               }
> > +                       }
> > +
> > +                       i915_vma_unpin_iomap(vma);
> > +
> > +                       vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, PIN_MAPPABLE);
> > +                       if (IS_ERR(vma)) {
> > +                               err = PTR_ERR(vma);
> > +                               goto out;
> > +                       }
> 
> GEM_BUG_ON(vma->view.type);
> -Chris

-- 
Ville Syrjälä
Intel
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