[Mesa-dev] [PATCH 16/22] anv/cmd_buffer: Add transition_color_buffer()

[Nanley Chery]

On Wed, May 03, 2017 at 02:24:19PM -0700, Jason Ekstrand wrote:
> On Thu, Apr 27, 2017 at 11:32 AM, Nanley Chery <nanleychery at gmail.com>
> wrote:
> 
> > Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
> > ---
> >  src/intel/vulkan/genX_cmd_buffer.c | 93 ++++++++++++++++++++++++++++++
> > ++++++++
> >  1 file changed, 93 insertions(+)
> >
> > diff --git a/src/intel/vulkan/genX_cmd_buffer.c
> > b/src/intel/vulkan/genX_cmd_buffer.c
> > index d5cc358aec..1ae0c3256e 100644
> > --- a/src/intel/vulkan/genX_cmd_buffer.c
> > +++ b/src/intel/vulkan/genX_cmd_buffer.c
> > @@ -454,6 +454,99 @@ genX(transfer_clear_value)(struct anv_cmd_buffer *
> > const cmd_buffer,
> >     }
> >  }
> >
> > +/* Transitions a color buffer from one layout to another. */
> > +static void
> > +transition_color_buffer(struct anv_cmd_buffer * const cmd_buffer,
> > +                        const struct anv_image * const image,
> > +                        const uint32_t base_level, uint32_t level_count,
> > +                        const uint32_t base_layer, uint32_t layer_count,
> > +                        const VkImageLayout initial_layout,
> > +                        const VkImageLayout final_layout)
> > +{
> > +   assert(cmd_buffer && image);
> > +
> > +   /* This must be a color image. */
> > +   assert(image->aspects == VK_IMAGE_ASPECT_COLOR_BIT);
> > +
> > +   /* Only color buffers with CCS need resolving.  */
> > +   if (image->aux_surface.isl.size == 0 || image->samples > 1)
> > +      return;
> > +
> > +   /* Don't transition this subresource range if it lacks auxiliary data.
> > */
> > +   if (base_level >= anv_color_aux_levels(image) ||
> > +       base_layer >= anv_color_aux_layers(image, base_level))
> > +      return;
> > +
> > +   /* The undefined layout indicates that the user doesn't care about the
> > +    * data that's currently in the buffer. The pre-initialized layout is
> > +    * equivalent to the undefined layout for optimally-tiled images.
> > +    *
> > +    * We can only skip the resolve for CCS_E images in this layout
> > because it
> > +    * is enabled outside of render passes. This allows previously
> > fast-cleared
> > +    * and undefined buffers to be defined with transfer operations.
> > +    */
> > +   const bool is_ccs_e = image->aux_usage == ISL_AUX_USAGE_CCS_E;
> > +   const bool undef_layout = initial_layout == VK_IMAGE_LAYOUT_UNDEFINED
> > ||
> > +                             initial_layout == VK_IMAGE_LAYOUT_
> > PREINITIALIZED;
> > +   if (is_ccs_e && undef_layout)
> > +      return;
> > +
> > +   /* A resolve isn't necessary when transitioning from a layout that
> > doesn't
> > +    * have fast-clear data or to a layout that will be aware of the
> > fast-clear
> > +    * value.
> > +    */
> > +   const bool maybe_fast_cleared = undef_layout || initial_layout ==
> > +                                   VK_IMAGE_LAYOUT_COLOR_
> > ATTACHMENT_OPTIMAL;
> > +   if (!maybe_fast_cleared || final_layout ==
> > +       VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL)
> > +      return;
> > +
> > +   /* Determine the optimal resolve operation. For now we only need to
> > resolve
> > +    * the clear color.
> > +    */
> > +   const enum blorp_fast_clear_op op = is_ccs_e ?
> > +                                       BLORP_FAST_CLEAR_OP_RESOLVE_PARTIAL
> > :
> > +                                       BLORP_FAST_CLEAR_OP_RESOLVE_FULL;
> > +
> > +   /* The actual range that will be transitioned is limited by the number
> > of
> > +    * subresources that have auxiliary data.
> > +    */
> > +   level_count = MIN2(level_count, anv_color_aux_levels(image));
> > +
> > +   /* A write cache flush with an end-of-pipe sync is required between
> > +    * rendering, clearing, and resolving operations. Perform a flush of
> > the
> > +    * write cache before and after the resolve operation to meet this
> > +    * requirement.
> > +    */
> >
> 
> anv_blorp.c has a more detailed comment about this.  I think I'd rather we
> copy it here so that it doesn't get lost when we delete
> ccs_resolve_attachments.
> 
> Also, I have no idea whether we need to do it per-fast-clear-op or once
> before we do fast-clear ops and once afterwards.  I think this is probably
> fine.
> 
> 

Contrary to the comment in anv_blorp, I found documentation that
provides us more information as to what's needed. How about I rewrite my
comment to this instead?

   From the Sky Lake PRM Vol. 7, "MCS Buffer for Render Target(s)":
   
      Any transition from any value in {Clear, Render, Resolve} to a
      different value in {Clear, Render, Resolve} requires end of pipe
      synchronization.
   
   Perform a flush of the write cache before and after the resolve
   operation to meet this requirement.

-Nanley

> > +   cmd_buffer->state.pending_pipe_bits |=
> > +      ANV_PIPE_RENDER_TARGET_CACHE_FLUSH_BIT | ANV_PIPE_CS_STALL_BIT;
> > +
> > +   for (uint32_t level = base_level; level < base_level + level_count;
> > level++) {
> > +
> > +      layer_count = MIN2(layer_count, anv_color_aux_layers(image, level));
> > +      for (uint32_t layer = base_layer; layer < base_layer + layer_count;
> > layer++) {
> > +
> > +         /* Create a surface state with the right clear color and perform
> > the
> > +          * resolve.
> > +          */
> > +         struct anv_state surface_state =
> > +            anv_cmd_buffer_alloc_surface_state(cmd_buffer);
> > +         anv_fill_ccs_resolve_ss(cmd_buffer->device, surface_state.map,
> > image,
> > +                                 level, layer);
> > +         add_image_relocs(cmd_buffer, image, VK_IMAGE_ASPECT_COLOR_BIT,
> > +                          is_ccs_e ?  ISL_AUX_USAGE_CCS_E :
> > ISL_AUX_USAGE_CCS_D,
> > +                          surface_state);
> > +         anv_state_flush(cmd_buffer->device, surface_state);
> > +         genX(transfer_clear_value)(cmd_buffer, surface_state, image,
> > level,
> > +                                    false);
> > +         anv_ccs_resolve(cmd_buffer, surface_state, image, level, layer,
> > op);
> > +      }
> > +   }
> > +
> > +   cmd_buffer->state.pending_pipe_bits |=
> > +      ANV_PIPE_RENDER_TARGET_CACHE_FLUSH_BIT | ANV_PIPE_CS_STALL_BIT;
> > +}
> > +
> >  /**
> >   * Setup anv_cmd_state::attachments for vkCmdBeginRenderPass.
> >   */
> > --
> > 2.12.2
> >
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