Re: [Intel-gfx] [PATCH] drm/i915: Tile F plane format support

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Sep 27, 2021 at 11:23:35AM -0700, Matt Roper wrote:
> On Thu, Sep 23, 2021 at 06:49:59PM +0300, Ville Syrjälä wrote:
> > On Thu, Sep 23, 2021 at 11:48:58AM +0300, Stanislav Lisovskiy wrote:
> > > TileF(Tile4 in bspec) format is 4K tile organized into
> > > 64B subtiles with same basic shape as for legacy TileY
> > > which will be supported by Display13.
> > 
> > Why we still haven't done the F->tile64 rename?
> >
> > This is the last chance to fix this before we bake 
> > this into the uapi and are stuck with a name that doesn't
> > match the spec and will just confuse everyone.
> 
> I think you're confusing the formats here.  The bspec uses both terms
> "TileF" and "Tile4" for the same format in different places.  There's a
> completely different format that's referred to as both "TileS" and
> "Tile64" in the bspec that we don't use at the moment.  So tile64
> wouldn't be a correct rename, but tile4 could be.

Right, tile64 is the macro tile variant I think. So like Ys
which we never bothered implementing, so I guess we''l not bother
with tile64 either.

> 
> In general Tile4 is much more common in the bspec than TileF is (TileF
> terminology is mostly found in the media sections).  And bspec 44917 is
> the most authoritative bspec page on the subject, and it refers to it as
> Tile4, so I agree that switching over "Tile4" would probably be a good
> move.
> 
> > 
> > > 
> ...
> > > diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> > > index bde5860b3686..d7dc421c6134 100644
> > > --- a/include/uapi/drm/i915_drm.h
> > > +++ b/include/uapi/drm/i915_drm.h
> > > @@ -1522,7 +1522,8 @@ struct drm_i915_gem_caching {
> > >  #define I915_TILING_NONE	0
> > >  #define I915_TILING_X		1
> > >  #define I915_TILING_Y		2
> > > -#define I915_TILING_LAST	I915_TILING_Y
> > > +#define I915_TILING_F		3
> > > +#define I915_TILING_LAST	I915_TILING_F
> > 
> > fences...
> 
> Recognizing TileF/Tile4 separately from TileY is important to code
> outside of display as well.  There are blitter instructions that require
> different settings for TileY vs Tile4/F so if we drop the tracking of
> this as a unique tiling type, it will break the blitting/copying and
> some of the upcoming local memory support for Xe_HP-based platforms.

These are uapi definitions for set_tiling(). You are not meant to add
anything there. Just like we didn't add anything for Yf.

-- 
Ville Syrjälä
Intel