[Mesa-dev] [PATCH 3/4] i965/gen9: Don't use encrypted MOCS

[Kenneth Graunke]

On Monday, June 22, 2015 05:24:11 PM Ben Widawsky wrote:
> On Thu, Jun 18, 2015 at 03:41:50PM -0700, Kenneth Graunke wrote:
> > On Wednesday, June 17, 2015 03:50:13 PM Ben Widawsky wrote:
> > > On gen9+ MOCS is an index into a table. It is 7 bits, and AFAICT, bit 0 is for
> > > doing encrypted reads.
> > > 
> > > I don't recall how I decided to do this for BXT. I don't know this patch was
> > > ever needed, since it seems nothing is broken today on SKL. Furthermore, this
> > > patch may no longer be needed because of the ongoing changes with MOCS setup. It
> > > is what is being used/tested, so it's included in the series.
> > > 
> > > The chosen values are the old values left shifted. That was also an arbitrary
> > > choice.
> > > 
> > > Cc:  Francisco Jerez <currojerez at riseup.net>
> > > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> > > ---
> > >  src/mesa/drivers/dri/i965/brw_defines.h | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/src/mesa/drivers/dri/i965/brw_defines.h b/src/mesa/drivers/dri/i965/brw_defines.h
> > > index bfcc442..5358edc 100644
> > > --- a/src/mesa/drivers/dri/i965/brw_defines.h
> > > +++ b/src/mesa/drivers/dri/i965/brw_defines.h
> > > @@ -2495,8 +2495,8 @@ enum brw_wm_barycentric_interp_mode {
> > >   * cache settings.  We still use only either write-back or write-through; and
> > >   * rely on the documented default values.
> > >   */
> > > -#define SKL_MOCS_WB 9
> > > -#define SKL_MOCS_WT 5
> > > +#define SKL_MOCS_WB 0x12
> > > +#define SKL_MOCS_WT 0xa
> > 
> > 
> > Yeah, it looks like Kristian made these defines the indices into the
> > table, but may have missed that the MOCS field puts that table index in
> > [6:1] and bit 0 is something else.
> > 
> > So shifting left by 1 seems like a good plan.  Perhaps write it as
> > 
> > #define SKL_MOCS_WB (0b000101 << 1)
> > #define SKL_MOCS_WT (0b001001 << 1)
> > 
> 
> You meant this, right (you reversed it, I think)?
> #define SKL_MOCS_WB (0b001001 << 1)
> #define SKL_MOCS_WT (0b000101 << 1)

Whoops!  Yes, that's what I meant.  Thanks!

--Ken
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