[Mesa-dev] [v3 4/6] i965/rbc: Consult rb settings for texture surface setup

Jason Ekstrand jason at jlekstrand.net
Fri Sep 9 14:11:16 UTC 2016


On Sep 8, 2016 11:13 PM, "Pohjolainen, Topi" <topi.pohjolainen at gmail.com>
wrote:
>
> On Thu, Sep 08, 2016 at 08:49:56AM -0700, Jason Ekstrand wrote:
> >    On Sep 7, 2016 9:30 PM, "Pohjolainen, Topi"
> >    <[1]topi.pohjolainen at gmail.com> wrote:
> >    >
> >    > On Wed, Sep 07, 2016 at 03:25:30PM -0700, Jason Ekstrand wrote:
> >    > >    On Sep 7, 2016 10:24 AM, "Topi Pohjolainen"
> >    > >    <[1][2]topi.pohjolainen at gmail.com> wrote:
> >    > >    >
> >    > >    > Once mcs buffer gets allocated without delay for lossless
> >    > >    > compression (same as we do for msaa), one gets regression
in:
> >    > >    >
> >    > >    > GL45-CTS.texture_barrier_ARB.same-texel-rw
> >    > >    >
> >    > >    > Setting the auxiliary surface for both sampling engine and
> >    data
> >    > >    > port seems to fix this. I haven't found any hardware
> >    documentation
> >    > >    > backing this though.
> >    > >    >
> >    > >    > v2 (Jason): Prepare also for the case where surface is
sampled
> >    with
> >    > >    >             non-compressible format forcing also rendering
> >    without
> >    > >    >             compression.
> >    > >    > v3: Split asserts and decision making.
> >    > >    >
> >    > >    > Signed-off-by: Topi Pohjolainen
> >    <[2][3]topi.pohjolainen at intel.com>
> >    > >    > ---
> >    > >    >  src/mesa/drivers/dri/i965/brw_wm_surface_state.c | 63
> >    > >    +++++++++++++++++++++---
> >    > >    >  1 file changed, 56 insertions(+), 7 deletions(-)
> >    > >    >
> >    > >    > diff --git
a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> >    > >    b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> >    > >    > index c1273c5..054c5c8 100644
> >    > >    > --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> >    > >    > +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> >    > >    > @@ -140,9 +140,7 @@ brw_emit_surface_state(struct
brw_context
> >    *brw,
> >    > >    >     struct isl_surf *aux_surf = NULL, aux_surf_s;
> >    > >    >     uint64_t aux_offset = 0;
> >    > >    >     enum isl_aux_usage aux_usage = ISL_AUX_USAGE_NONE;
> >    > >    > -   if (mt->mcs_mt &&
> >    > >    > -       ((view.usage & ISL_SURF_USAGE_RENDER_TARGET_BIT) ||
> >    > >    > -        mt->fast_clear_state !=
> >    INTEL_FAST_CLEAR_STATE_RESOLVED)) {
> >    > >    > +   if (mt->mcs_mt && !(flags & INTEL_AUX_BUFFER_DISABLED))
{
> >    > >    >        intel_miptree_get_aux_isl_surf(brw, mt, &aux_surf_s,
> >    > >    &aux_usage);
> >    > >    >        aux_surf = &aux_surf_s;
> >    > >    >        assert(mt->mcs_mt->offset == 0);
> >    > >    > @@ -425,6 +423,54 @@ swizzle_to_scs(GLenum swizzle, bool
> >    > >    need_green_to_blue)
> >    > >    >     return (need_green_to_blue && scs == HSW_SCS_GREEN) ?
> >    > >    HSW_SCS_BLUE : scs;
> >    > >    >  }
> >    > >    >
> >    > >    > +static unsigned
> >    > >    > +brw_find_matching_rb(const struct gl_framebuffer *fb,
> >    > >    > +                     const struct intel_mipmap_tree *mt)
> >    > >    > +{
> >    > >    > +   for (unsigned i = 0; i < fb->_NumColorDrawBuffers; i++)
{
> >    > >    > +      const struct intel_renderbuffer *irb =
> >    > >    > +         intel_renderbuffer(fb->_ColorDrawBuffers[i]);
> >    > >    > +
> >    > >    > +      if (irb->mt == mt)
> >    > >    > +         return i;
> >    > >    > +   }
> >    > >    > +
> >    > >    > +   return fb->_NumColorDrawBuffers;
> >    > >    > +}
> >    > >    > +
> >    > >    > +static bool
> >    > >    > +brw_disable_aux_surface(const struct brw_context *brw,
> >    > >    > +                        const struct intel_mipmap_tree *mt)
> >    > >    > +{
> >    > >    > +   /* Nothing to disable. */
> >    > >    > +   if (!mt->mcs_mt)
> >    > >    > +      return false;
> >    > >    > +
> >    > >    > +   /* There are special cases only for lossless
compression.
> >    */
> >    > >    > +   if (!intel_miptree_is_lossless_compressed(brw, mt))
> >    > >    > +      return mt->fast_clear_state ==
> >    > >    INTEL_FAST_CLEAR_STATE_RESOLVED;
> >    > >    > +
> >    > >    > +   const struct gl_framebuffer *fb = brw->ctx.DrawBuffer;
> >    > >    > +   const unsigned rb_index = brw_find_matching_rb(fb, mt);
> >    > >    > +
> >    > >    > +   /* In practise it looks that setting the same lossless
> >    compressed
> >    > >    surface
> >    > >    > +    * to be sampled without auxiliary surface and to be
> >    written with
> >    > >    auxiliary
> >    > >    > +    * surface confuses the hardware. Therefore sampler
engine
> >    must
> >    > >    be provided
> >    > >    > +    * with auxiliary buffer regardless of the fast clear
> >    state if
> >    > >    the same
> >    > >    > +    * surface is also going to be written during the same
> >    rendering
> >    > >    pass with
> >    > >    > +    * auxiliary buffer enabled.
> >    > >    > +    */
> >    > >    > +   if (rb_index < fb->_NumColorDrawBuffers) {
> >    > >    > +      if (brw->draw_aux_buffer_disabled[rb_index]) {
> >    > >    > +         assert(mt->fast_clear_state ==
> >    > >    INTEL_FAST_CLEAR_STATE_RESOLVED);
> >    > >    > +      }
> >    > >    > +
> >    > >    > +      return brw->draw_aux_buffer_disabled[rb_index];
> >    > >
> >    > >    Can we use "mt->fast_clear_state ==
> >    INTEL_FAST_CLEAR_STATE_RESOLVED"
> >    > >    here as well?  For render targets we want to look at
> >    > >    aux_buffer_disabled but for textures (which is the only case
> >    that uses
> >    > >    this function), fast_clear_state should be sufficient.
> >    >
> >    > Like the comment says, we can't skip setting aux buffer for
sampling
> >    in case
> >    > the same surface is written as render target with aux enabled.
> >    Hardware
> >    > doesn't seem to like this. This is specifically for that purpose
> >    checking
> >    > the flag.
> >
> >    Let me see if I understand this correctly: this handles the case
where
> >    the miptree is bound as both a render target and a texture and there
is
> >    nothing about the texture view scenario causing it to skip
compression
> >    and, for some reason, the surface starts of the draw call fully
> >    resolved.  If *any* drawing has been done without a resolve, we would
> >    be in the UNRESOLVED state and this wouldn't be needed.  That's
> >    terribly specific but also a valid use case.
> >
> >    We could potentially handle this by setting the render target
surfaces
> >    to UNRESOLVED a bit earlier in the pipeline setup code.  I believe we
> >    flag things as unresolved rather late; in particular, after we've
done
> >    our texture state setup. The other option is to do exactly what you
did
> >    and add a comment.  That's probably the best option.  With a good
> >    comment added,
>
> So, above there is already:
>
>     * In practise it looks that setting the same lossless compressed
surface
>     * to be sampled without auxiliary surface and to be written with
auxiliary
>     * surface confuses the hardware. Therefore sampler engine must be
provided
>     * with auxiliary buffer regardless of the fast clear state if the same
>     * surface is also going to be written during the same rendering pass
with
>     * auxiliary buffer enabled.
>
> What would you add?

Hmmm... I think my reservations about that convent are because it sounds
like a workaround.  How about this:

If we are drawing into this with compression enabled, then we must also
enable compression when texturing from it regardless of fast_clear_state.
If we don't then, after the first draw call with this setup, there will be
data in the CCS which won't get picked up by subsequent texturing
operations as required by ARB_texture_barrier.  Since we don't want to
re-emit the binding table or do a resolve operation every draw call, the
easiest thing to do is just enable compression on the texturing side.  This
is completely safe to do since, if compressed texturing weren't allowed, we
would have disabled compression of render targets in
whatever_that_function_is_called().

> >
> >    Reviewed-by: Jason Ekstrand <[4]jason at jlekstrand.net>
> >
> >    --Jason
> >
> >    > >
> >    > >    > +   }
> >    > >    > +
> >    > >    > +   return mt->fast_clear_state ==
> >    INTEL_FAST_CLEAR_STATE_RESOLVED;
> >    > >    > +}
> >    > >    > +
> >    > >    >  void
> >    > >    >  brw_update_texture_surface(struct gl_context *ctx,
> >    > >    >                             unsigned unit,
> >    > >    > @@ -542,7 +588,8 @@ brw_update_texture_surface(struct
> >    gl_context
> >    > >    *ctx,
> >    > >    >            obj->Target == GL_TEXTURE_CUBE_MAP_ARRAY)
> >    > >    >           view.usage |= ISL_SURF_USAGE_CUBE_BIT;
> >    > >    >
> >    > >    > -      const int flags = 0;
> >    > >    > +      const int flags =
> >    > >    > +         brw_disable_aux_surface(brw, mt) ?
> >    > >    INTEL_AUX_BUFFER_DISABLED : 0;
> >    > >    >        brw_emit_surface_state(brw, mt, flags, mt->target,
> >    view,
> >    > >    >
> >    surface_state_infos[brw->gen].tex_mocs,
> >    > >    >                               surf_offset, surf_index,
> >    > >    > @@ -1113,7 +1160,8 @@
update_renderbuffer_read_surfaces(struct
> >    > >    brw_context *brw)
> >    > >    >                 .usage = ISL_SURF_USAGE_TEXTURE_BIT,
> >    > >    >              };
> >    > >    >
> >    > >    > -            const int flags = 0;
> >    > >    > +            const int flags =
> >    brw->draw_aux_buffer_disabled[i] ?
> >    > >    > +                                 INTEL_AUX_BUFFER_DISABLED
:
> >    0;
> >    > >    >              brw_emit_surface_state(brw, irb->mt, flags,
> >    target,
> >    > >    view,
> >    > >    >
> >    > >    surface_state_infos[brw->gen].tex_mocs,
> >    > >    >                                     surf_offset, surf_index,
> >    > >    > @@ -1672,8 +1720,9 @@ update_image_surface(struct
brw_context
> >    *brw,
> >    > >    >              };
> >    > >    >
> >    > >    >              const int surf_index = surf_offset -
> >    > >    &brw->wm.base.surf_offset[0];
> >    > >    > -
> >    > >    > -            const int flags = 0;
> >    > >    > +            const int flags =
> >    > >    > +               mt->fast_clear_state ==
> >    > >    INTEL_FAST_CLEAR_STATE_RESOLVED ?
> >    > >    > +               INTEL_AUX_BUFFER_DISABLED : 0;
> >    > >
> >    > >    According to brw_context, images should *always* be resolved.
> >    Can we
> >    > >    make this check an assert and always pass AUX_BUFFER_DISABLED?
> >    > >
> >    > >    >              brw_emit_surface_state(brw, mt, flags,
> >    mt->target, view,
> >    > >    >
> >    > >    surface_state_infos[brw->gen].tex_mocs,
> >    > >    >                                     surf_offset, surf_index,
> >    > >    > --
> >    > >    > 2.5.5
> >    > >    >
> >    > >    > _______________________________________________
> >    > >    > mesa-dev mailing list
> >    > >    > [3][5]mesa-dev at lists.freedesktop.org
> >    > >    > [4][6]
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >    > >
> >    > > References
> >    > >
> >    > >    1. mailto:[7]topi.pohjolainen at gmail.com
> >    > >    2. mailto:[8]topi.pohjolainen at intel.com
> >    > >    3. mailto:[9]mesa-dev at lists.freedesktop.org
> >    > >    4. [10]https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
> > References
> >
> >    1. mailto:topi.pohjolainen at gmail.com
> >    2. mailto:topi.pohjolainen at gmail.com
> >    3. mailto:topi.pohjolainen at intel.com
> >    4. mailto:jason at jlekstrand.net
> >    5. mailto:mesa-dev at lists.freedesktop.org
> >    6. https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >    7. mailto:topi.pohjolainen at gmail.com
> >    8. mailto:topi.pohjolainen at intel.com
> >    9. mailto:mesa-dev at lists.freedesktop.org
> >   10. https://lists.freedesktop.org/mailman/listinfo/mesa-dev
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