[Intel-gfx] [PATCH] drm/i915/mtl: Media GT and Render GT share common GGTT

[Matt Roper]

On Mon, Nov 07, 2022 at 07:43:59PM +0530, Iddamsetty, Aravind wrote:
> 
> 
> On 31-10-2022 23:16, Matt Roper wrote:
> > On Mon, Oct 31, 2022 at 06:01:11PM +0530, Aravind Iddamsetty wrote:
> >> On XE_LPM+ platforms the media engines are carved out into a separate
> >> GT but have a common GGTMMADR address range which essentially makes
> >> the GGTT address space to be shared between media and render GT.
> > 
> 
> <snip>
> >>  
> >>  int intel_gt_init_mmio(struct intel_gt *gt)
> >> @@ -965,6 +973,9 @@ int intel_gt_tiles_init(struct drm_i915_private *i915)
> >>  	int ret;
> >>  
> >>  	for_each_gt(gt, i915, id) {
> >> +		if (GRAPHICS_VER(i915) >= 8)
> >> +			setup_private_pat(gt);
> >> +
> > 
> > Since the term "tile" is used for PVC-style remote tiles (which we have
> > some framework for, but haven't enabled yet), it seems confusing to have
> > the PAT setup for all GTs (including the standalone media GT) in a
> > function called intel_gt_tiles_init().  Maybe we should also have a prep
> > patch that renames this function if we're going to start doing non-tile
> > things in here too?
> 
> But isn't GT and Tile used interchangeably. Also, Could you please

The terminology has been used a bit inconsistently so far, but I think
we're trying to standardize on "tile" as referring to the PVC-style
combination of "GT + LMEM."  So I'd consider MTL's standalone media to
be a "GT," but not a "tile" because it isn't paired with its own lmem
unit.


Matt

> elaborate what do you mean by non tile related things here and as i
> understand PAT are per GT registers and in case of SA Media the
> gsi_offset get added.
> > 
> >>  		ret = intel_gt_probe_lmem(gt);
> >>  		if (ret)
> >>  			return ret;
> <snip>
> 
> Thanks,
> Aravind.

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation