[PATCH] drm/i915/gem: Calculate object page offset for partial memory mapping

[Andi Shyti]

Hi Nirmoy,

...

> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> > index a2195e28b625..57a2dda2c3cc 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> > @@ -276,7 +276,7 @@ static vm_fault_t vm_fault_cpu(struct vm_fault *vmf)
> >   	/* PTEs are revoked in obj->ops->put_pages() */
> >   	err = remap_io_sg(area,
> >   			  area->vm_start, area->vm_end - area->vm_start,
> > -			  obj->mm.pages->sgl, iomap);
> > +			  obj->mm.pages->sgl, 0, iomap);
> 
> Why don't we need partial mmap for CPU but only for GTT ?

As far as I understood we don't. I have a version with the CPU
offset as well in trybot[*]

But without support for segmented buffer objects, I don't know
how much this has any effect.

> Sounds like this also need to be cover by a IGT tests.

Yes, I it does need some igt work, working on it.

> Don't we need "Fixes" tag for this?

Why should we? I'm not fixing anything here, I'm just
recalculating the mapping not starting from the beginning of the
scatter page.

Andi

[*] https://patchwork.freedesktop.org/patch/584474/?series=131539&rev=2