[Intel-gfx] [PATCH 00/13] Gen7 batch buffer command parser

[Volkin, Bradley D]

On Wed, Mar 05, 2014 at 09:14:38AM -0800, Daniel Vetter wrote:
> On Wed, Mar 05, 2014 at 08:59:56AM -0800, Volkin, Bradley D wrote:
> > On Wed, Mar 05, 2014 at 02:46:35AM -0800, Daniel Vetter wrote:
> > > On Tue, Feb 18, 2014 at 10:15:44AM -0800, bradley.d.volkin at intel.com wrote:
> > > > From: Brad Volkin <bradley.d.volkin at intel.com>
> > > > 3) Coherency. I've previously found a coherency issue on VLV when reading the
> > > >    batch buffer from the CPU during execbuffer2. Userspace writes the batch via
> > > >    pwrite fast path before calling execbuffer2. The parser reads stale data.
> > > >    This works fine on IVB and HSW, so I believe it's an LLC vs. non-LLC issue.
> > > >    It's possible that the shmem pread refactoring fixes this, I just have not
> > > >    been able to retest due to lack of a VLV system.
> > > 
> > > Is it still true that we need to test this on vlv? The shmem_pread path
> > > really should have fixed this ... Otherwise I think this looks ready to go
> > > in, I'll pester Jani for the review.
> > 
> > Yes, I still don't have a system to test on.
> 
> Steal one? I guess we'll notice when our QA runs all this stuff on theirs
> ;-)

It's not stealing if I give it back :)

Anyhow, sorry, the note isn't totally clear. It shouldn't be a problem for now because
the parser is still disabled on VLV (and platforms with ppgtt disabled in general). I
will look into retesting this though.

Brad

> 
> Cheers, Daniel
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch