Re: [PATCH 1/5] drm/i915: Place the Global GTT VM first in the list of VM

[Ben Widawsky <benjamin.widawsky@intel.com>]

On Sat, Jan 25, 2014 at 01:31:29PM -0800, Kenneth Graunke wrote:
> On 01/25/2014 12:48 PM, Daniel Vetter wrote:
> > On Sat, Jan 25, 2014 at 12:32:33AM -0800, Kenneth Graunke wrote:
> >> On 01/24/2014 06:17 PM, Ben Widawsky wrote:
> >>> From: Chris Wilson <chris@chris-wilson.co.uk>
> >>>
> >>> This is useful for debugging as we then know that the first entry is
> >>> always the global GTT, and all later entries the per-process GTT VM.
> >>>
> >>> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> >>> Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
> >>> ---
> >>>  drivers/gpu/drm/i915/i915_gem.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> >>> index 024e454..946a577 100644
> >>> --- a/drivers/gpu/drm/i915/i915_gem.c
> >>> +++ b/drivers/gpu/drm/i915/i915_gem.c
> >>> @@ -4634,7 +4634,7 @@ void i915_init_vm(struct drm_i915_private *dev_priv,
> >>>  	INIT_LIST_HEAD(&vm->active_list);
> >>>  	INIT_LIST_HEAD(&vm->inactive_list);
> >>>  	INIT_LIST_HEAD(&vm->global_link);
> >>> -	list_add(&vm->global_link, &dev_priv->vm_list);
> >>> +	list_add_tail(&vm->global_link, &dev_priv->vm_list);
> >>>  }
> >>>  
> >>>  void
> >>
> >> These five patches are:
> >> Tested-by: Kenneth Graunke <kenneth@whitecape.org>
> >>
> >> On Broadwell with drm-intel-nightly, I don't get the batchbuffer as part
> >> of my error state, which is a regression.  With these patches, it's back
> >> again.
> >>
> >> Thanks for investigating this, Ben.
> > 
> > I want to merge Mika's fixes for the reset stats ioctls, mostly since his
> > patches are older and we also have neat testcases for them all. Then we
> > can reconsider the issue here and how to best get at the right batch
> > buffers. If it breaks development just boot with ppgtt=1 for now, for
> > userspace nothing really changes compared to full ppgtt.
> > -Daniel
> > 
> 
> Do you mean i915.i915_enable_ppgtt=1?  I still get no batchbuffer in the
> error state either with or without that.
> 
> But for now, Ben gave me a branch that fixes the issue, so I'll just
> keep using that until you get this sorted in next/nightly.
> 
> --Ken
> 

Daniel, the issue is exactly with aliasing (any platform >= gen7 with
aliasing to be precise). I did ask Ken to try some of Mika's patches
before pursuing this, but since then I've asked Mika to send me exactly
what I need to review. I am not sure they are exactly what I asked Ken
to test.

In any case, I will try to review Mika's patches by Monday, however a
quick glance lead me to believe they are unrelated to this.

-- 
Ben Widawsky, Intel Open Source Technology Center