[Mesa-dev] [PATCH v2] anv/blorp: Do more flushing around HiZ clears

[Jason Ekstrand]

On Fri, Aug 31, 2018 at 5:38 PM Nanley Chery <nanleychery at gmail.com> wrote:

> On Fri, Aug 31, 2018 at 05:15:53PM -0500, Jason Ekstrand wrote:
> > We make the flush after a HiZ clear unconditional and add a flush/stall
> > before the clear as well.
> >
> > Cc: mesa-stable at lists.freedesktop.org
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107760
> > ---
> >  src/intel/vulkan/anv_blorp.c | 44 +++++++++++++++++++++++++++---------
> >  1 file changed, 33 insertions(+), 11 deletions(-)
> >
> > diff --git a/src/intel/vulkan/anv_blorp.c b/src/intel/vulkan/anv_blorp.c
> > index 35b304f92b3..04bca4d261f 100644
> > --- a/src/intel/vulkan/anv_blorp.c
> > +++ b/src/intel/vulkan/anv_blorp.c
> > @@ -1604,6 +1604,24 @@ anv_image_hiz_clear(struct anv_cmd_buffer
> *cmd_buffer,
> >                                     ISL_AUX_USAGE_NONE, &stencil);
> >     }
> >
> > +   /* From the Sky Lake PRM Volume 7, "Depth Buffer Clear":
> > +    *
> > +    *    "The following is required when performing a depth buffer
> clear with
> > +    *    using the WM_STATE or 3DSTATE_WM:
> > +    *
> > +    *       * If other rendering operations have preceded this clear, a
> > +    *         PIPE_CONTROL with depth cache flush enabled, Depth Stall
> bit
> > +    *         enabled must be issued before the rectangle primitive
> used for
> > +    *         the depth buffer clear operation.
> > +    *       * [...]"
> > +    *
> > +    * Even though the PRM only says that this is required if using
> 3DSTATE_WM
> > +    * and a 3DPRIMITIVE, it appears to also sometimes hang when doing a
> clear
> > +    * with WM_HZ_OP.
>                            ^
> This part was a little hard to parse because the PRM hasn't mentioned
> the hardware hanging and the subject's changed from the pipecontrol to
> the GPU. Maybe replace it with something like the following?
>
>                            the GPU appears to also need this to avoid
>                            occasional hangs when doing a clear with
>                            WM_HZ_OP.
>

Works for me.


> We could discuss it more on IRC if you prefer.
>
> With that changed, this patch is
> Reviewed-by: Nanley Chery <nanley.g.chery at intel.com>
>

Thanks!


> > +    */
> > +   cmd_buffer->state.pending_pipe_bits |=
> > +      ANV_PIPE_DEPTH_CACHE_FLUSH_BIT | ANV_PIPE_DEPTH_STALL_BIT;
> > +
> >     blorp_hiz_clear_depth_stencil(&batch, &depth, &stencil,
> >                                   level, base_layer, layer_count,
> >                                   area.offset.x, area.offset.y,
> > @@ -1618,18 +1636,22 @@ anv_image_hiz_clear(struct anv_cmd_buffer
> *cmd_buffer,
> >
> >     /* From the SKL PRM, Depth Buffer Clear:
> >      *
> > -    * Depth Buffer Clear Workaround
> > -    * Depth buffer clear pass using any of the methods (WM_STATE,
> 3DSTATE_WM
> > -    * or 3DSTATE_WM_HZ_OP) must be followed by a PIPE_CONTROL command
> with
> > -    * DEPTH_STALL bit and Depth FLUSH bits “set” before starting to
> render.
> > -    * DepthStall and DepthFlush are not needed between consecutive
> depth clear
> > -    * passes nor is it required if the depth-clear pass was done with
> > -    * “full_surf_clear” bit set in the 3DSTATE_WM_HZ_OP.
> > +    *    "Depth Buffer Clear Workaround
> > +    *
> > +    *    Depth buffer clear pass using any of the methods (WM_STATE,
> > +    *    3DSTATE_WM or 3DSTATE_WM_HZ_OP) must be followed by a
> PIPE_CONTROL
> > +    *    command with DEPTH_STALL bit and Depth FLUSH bits “set” before
> > +    *    starting to render.  DepthStall and DepthFlush are not needed
> between
> > +    *    consecutive depth clear passes nor is it required if the
> depth-clear
> > +    *    pass was done with “full_surf_clear” bit set in the
> > +    *    3DSTATE_WM_HZ_OP."
> > +    *
> > +    * Even though the PRM provides a bunch of conditions under which
> this is
> > +    * supposedly unnecessary, we choose to perform the flush
> unconditionally
> > +    * just to be safe.
> >      */
> > -   if (aspects & VK_IMAGE_ASPECT_DEPTH_BIT) {
> > -      cmd_buffer->state.pending_pipe_bits |=
> > -         ANV_PIPE_DEPTH_CACHE_FLUSH_BIT | ANV_PIPE_DEPTH_STALL_BIT;
> > -   }
> > +   cmd_buffer->state.pending_pipe_bits |=
> > +      ANV_PIPE_DEPTH_CACHE_FLUSH_BIT | ANV_PIPE_DEPTH_STALL_BIT;
> >  }
> >
> >  void
> > --
> > 2.17.1
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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