[Mesa-stable] [Mesa-dev] [PATCH v2 3/6] i965/surface_state: Drop brw_aux_surface_disabled

[Kenneth Graunke]

On Wednesday, January 24, 2018 12:37:21 PM PST Jason Ekstrand wrote:
> The only purpose of this function is to disable aux on texture surfaces
> when the corresponding renderbuffer has aux disabled.  However, the act
> of disabling aux on the renderbuffer will cause it to be resolved and
> intel_miptree_texture_aux_usage will already check the resolved status
> of a texture and return ISL_AUX_USAGE_NONE for it.  Even if we used CCS
> for it, that wouldn't really be a problem because the CCS will be in the
> pass-through state and so it would effectively be ignored.
> 
> Cc: mesa-stable at lists.freedesktop.org
> ---
>  src/mesa/drivers/dri/i965/brw_wm_surface_state.c | 20 --------------------
>  1 file changed, 20 deletions(-)

Okay, so this does make a change... if you have an array texture, and
bind a single layer of it as a render target...causing a self-dependency
for that layer...then we'll resolve that one layer.  But the rest will
have CCS data still.  intel_miptree_texture_aux_usage will only switch
to NONE if *all* the layers have no CCS data, so it'll keep using CCS.

But on IRC you convinced me that this is okay.  That one slice's CCS
buffer will have everything in the pass-through state ("go look at the
actual surface").  The texturing SURFACE_STATE will use CCS, and the
render target's SURFACE_STATE will be None.  So, rendering won't
compress new data...it'll just update the underlying surface.  Sampling
from that slice will also go to the underlying surface.  But, sampling
from other slices will still get compression, which is actually better.

Patch 6 is also good...it'll make us only resolve the slice bound for
rendering, and not all the slices bound for texturing when one has a
conflict.

Series is:
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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