Re: [PATCH] drm/i915/bdw: Fix GEN8 GTT size calculation

[Ben Widawsky <ben@bwidawsk.net>]

On Fri, Mar 14, 2014 at 07:40:30PM +0100, Daniel Vetter wrote:
> On Fri, Mar 14, 2014 at 09:58:06AM -0700, Ben Widawsky wrote:
> > The preliminary HW support check is no longer needed, and the
> > calculation is simplified while here.
> > 
> > Reported-by: David Woodhouse <David.Woodhouse@intel.com>
> > Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 9 +--------
> >  1 file changed, 1 insertion(+), 8 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 40a2b36..694112a 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -1250,14 +1250,7 @@ static inline unsigned int gen8_get_total_gtt_size(u16 bdw_gmch_ctl)
> >  {
> >  	bdw_gmch_ctl >>= BDW_GMCH_GGMS_SHIFT;
> >  	bdw_gmch_ctl &= BDW_GMCH_GGMS_MASK;
> > -	if (bdw_gmch_ctl)
> > -		bdw_gmch_ctl = 1 << bdw_gmch_ctl;
> > -	if (bdw_gmch_ctl > 4) {
> > -		WARN_ON(!i915_preliminary_hw_support);
> > -		return 4<<20;
> > -	}
> > -
> > -	return bdw_gmch_ctl << 20;
> > +	return 1 << (bdw_gmch_ctl + 20);
> 
> I don't have this in my tree, and it seems to never have existed in
> upstream ...
> 
> /me is confused
> 
> Cheers, Daniel
> 

This was based off of linus master, since I assumed that is what David
was using. Honestly, I hadn't looked at our Intel trees. Maybe we're
good here already.


-- 
Ben Widawsky, Intel Open Source Technology Center