[Mesa-dev] [PATCH 3/4] i965/tex_image: Reference the renderbuffer miptree in setTexBuffer2

[Chad Versace]

On Tue 12 Sep 2017, Jason Ekstrand wrote:
> The old code made a new miptree that referenced the same BO as the
> renderbuffer and just trusted in the memory aliasing to work.  There are
> only two ways in which the new miptree is liable to differ from the one
> in the renderbuffer and neither of them matter:
> 
>  1) It may have a different target.  The only targets that we can ever
>     see in intelSetTexBuffer2 are GL_TEXTURE_2D and GL_TEXTURE_RECTANGLE
>     and the difference between the two doesn't matter as far as the
>     miptree is concerned; genX(update_sampler_state) only looks at the
>     gl_texture_object and not the miptree when determining whether or
>     not to use normalized coordinates.
> 
>  2) It may have a very slightly different format.  Again, this doesn't
>     matter because we've supported texture views for quite some time so
>     we always look at the gl_texture_object format instead of the
>     miptree format for hardware setup anyway.
> 
> On the other hand, because we were recreating the miptree, we were using
> intel_miptree_create_for_bo which doesn't understand modifiers.  We
> really want this function to work without doing a resolve so long as you
> have modifiers so we need to fix that.
> ---
>  src/mesa/drivers/dri/i965/intel_tex_image.c | 23 ++++-------------------
>  1 file changed, 4 insertions(+), 19 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/intel_tex_image.c b/src/mesa/drivers/dri/i965/intel_tex_image.c


>     intel_miptree_make_shareable(brw, rb->mt);
> -   mt = intel_miptree_create_for_bo(brw, rb->mt->bo, texFormat, 0,
> -                                    rb->Base.Base.Width,
> -                                    rb->Base.Base.Height,
> -                                    1, rb->mt->surf.row_pitch,
> -                                    MIPTREE_CREATE_DEFAULT);
> -   if (mt == NULL)
> -       return;
> -   mt->target = target;

>     _mesa_lock_texture(&brw->ctx, texObj);
>     texImage = _mesa_get_tex_image(ctx, texObj, target, 0);
> -   intel_set_texture_image_mt(brw, texImage, internal_format, mt);
> -   intel_miptree_release(&mt);
> +   intel_set_texture_image_mt(brw, texImage, internal_format, rb->mt);
>     _mesa_unlock_texture(&brw->ctx, texObj);

The above hunk looks like the logical conclusion of consecutive commits
40e9be4 and 8ceb7c7. In fact, it seems like this was commit's 8ceb7c7
actual intention.

Reviewed-by: Chad Versace <chadversary at chromium.org>