Re: [PATCH] gem_pin: Be explicit about GGTT needs

[Ben Widawsky <ben@bwidawsk.net>]

On Thu, Nov 07, 2013 at 07:36:50PM +0100, Daniel Vetter wrote:
> On Thu, Nov 7, 2013 at 7:11 PM, Ben Widawsky <ben@bwidawsk.net> wrote:
> >> > @@ -63,7 +65,7 @@ static void exec(int fd, uint32_t handle, uint32_t offset)
> >> >     gem_exec[0].relocs_ptr = (uintptr_t) gem_reloc;
> >> >     gem_exec[0].alignment = 0;
> >> >     gem_exec[0].offset = 0;
> >> > -   gem_exec[0].flags = 0;
> >> > +   gem_exec[0].flags = LOCAL__EXEC_OBJ_NEEDS_GTT;
> >>
> >> This only really works with the aliasing ppgtt stuff on gen6, I'd just
> >> skip the test -it's not really useful with real ppgtt.
> >> -Daniel
> >
> > It is really useful with real ppgtt. Please rethink your assertion.
> 
> The test links up the global gtt used by the current pin ioctl with
> the ppgtt. That's not useful, except when they alias. If we want
> soft-pinning, then we need a new ioctl mode to return the right
> address from the right address space. Which means a new (sub)test.
> -Daniel

This is only indirectly related to soft pinning. No context will ever have the
global GTT address space. If you want to support the pin IOCTL, (which
Chris has before said he requires - the original patch series disabled
it) you must do this. We already have a flag that does what we want,
and, demonstrably, a test which exercises it.

I do not think a new ioctl, nor a new subtest is the solution for this.

-- 
Ben Widawsky, Intel Open Source Technology Center