Re: [PATCH 08/15] drm/i915: Fix up checks for aliasing ppgtt

From: "Thierry, Michel" <michel.thierry@intel.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH 08/15] drm/i915: Fix up checks for aliasing ppgtt
Date: Fri, 8 Aug 2014 14:00:33 +0000	[thread overview]
Message-ID: <40F8A24546556F4F886C42CCE2ED59E51B2C10FA@IRSMSX103.ger.corp.intel.com> (raw)
In-Reply-To: <20140808134919.GS8727@phenom.ffwll.local>


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> -----Original Message-----
> From: Daniel Vetter [mailto:daniel.vetter@ffwll.ch] On Behalf Of Daniel
> Vetter
> Sent: Friday, August 08, 2014 2:49 PM
> To: Thierry, Michel
> Cc: Daniel Vetter; Intel Graphics Development
> Subject: Re: [Intel-gfx] [PATCH 08/15] drm/i915: Fix up checks for
aliasing
> ppgtt
> 
> On Fri, Aug 08, 2014 at 01:03:53PM +0000, Thierry, Michel wrote:
> >
> > > -----Original Message-----
> > > From: Intel-gfx [mailto:intel-gfx-bounces@lists.freedesktop.org] On
> Behalf
> > > Of Daniel Vetter
> > > Sent: Wednesday, August 06, 2014 2:05 PM
> > > To: Intel Graphics Development
> > > Cc: Daniel Vetter
> > > Subject: [Intel-gfx] [PATCH 08/15] drm/i915: Fix up checks for
aliasing
> > ppgtt
> > >
> > > A subsequent patch will no longer initialize the aliasing ppgtt if we
> > > have full ppgtt enabled, since we simply don't need that any more.
> > >
> > > Unfortunately a few places check for the aliasing ppgtt instead of
> > > checking for ppgtt in general. Fix them up.
> > >
> > > One special case are the gtt offset and size macros, which have some
> > > code to remap the aliasing ppgtt to the global gtt. The aliasing ppgtt
> > > is _not_ a logical address space, so passing that in as the vm is
> > > plain and simple a bug. So just WARN about it and carry on - we have a
> > > gracefully fall-through anyway if we can't find the vma.
> > >
> > > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > ---
> > >  drivers/gpu/drm/i915/i915_cmd_parser.c  | 4 +---
> > >  drivers/gpu/drm/i915/i915_dma.c         | 2 +-
> > >  drivers/gpu/drm/i915/i915_gem.c         | 8 ++------
> > >  drivers/gpu/drm/i915/intel_ringbuffer.c | 4 +---
> > >  4 files changed, 5 insertions(+), 13 deletions(-)
> > >
> > > --
> > > 1.9.3
> > >
> > Sorry, I spotted another instance in gen8_ppgtt_info (debugfs). It is
more
> > gen8_ppgtt_info's fault, so I'm sending a follow up patch for it.
> > Unless you want to combine them...
> > Reviewed-by: Michel Thierry <michel.thierry@intel.com>
> 
> Actually I spotted that one and decided that I can't break things worse
> than it is - the aliasing ppgtt for full ppgtt is completely unused
> (except for these checks), so dumping it doesn't add value.
> 
> To check: Does your r-b apply here still even without any fixup for gen8
> ppgtt_info?
> -Daniel
Yes, the r-b still applies. 
And you're also right about gen8_ppgtt_info, it wouldn't print anything
useful in its current state.
-Michel
> 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 
> 
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch

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