[Mesa-dev] [PATCH 23/28] i965/blorp: Add support for W-[de]tiling to the NIR path

Pohjolainen, Topi topi.pohjolainen at intel.com
Fri May 13 05:32:00 UTC 2016


On Tue, May 10, 2016 at 04:16:43PM -0700, Jason Ekstrand wrote:
> ---
>  src/mesa/drivers/dri/i965/brw_blorp_blit.cpp | 107 ++++++++++++++++++++++++++-
>  1 file changed, 105 insertions(+), 2 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> index 27aab20..c0c02cf 100644
> --- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> @@ -571,6 +571,98 @@ blorp_nir_txf_ms_mcs(nir_builder *b, nir_ssa_def *pos)
>     return &tex->dest.ssa;
>  }
>  
> +static nir_ssa_def *
> +nir_mask_shift_or(struct nir_builder *b, nir_ssa_def *dst, nir_ssa_def *src,
> +                  uint32_t src_mask, int src_left_shift)
> +{
> +   nir_ssa_def *masked = nir_iand(b, src, nir_imm_int(b, src_mask));
> +
> +   nir_ssa_def *shifted;
> +   if (src_left_shift > 0) {
> +      shifted = nir_ishl(b, masked, nir_imm_int(b, src_left_shift));
> +   } else if (src_left_shift < 0) {
> +      shifted = nir_ushr(b, masked, nir_imm_int(b, -src_left_shift));
> +   } else {
> +      assert(src_left_shift == 0);
> +      shifted = masked;
> +   }
> +
> +   return nir_ior(b, dst, shifted);
> +}

We could keep original documentation here also:

/**
 * Emit code to compensate for the difference between Y and W tiling.
 *
 * This code modifies the X and Y coordinates according to the formula:
 *
 *   (X', Y', S') = detile(new_tiling, tile(old_tiling, X, Y, S))
 *
 * (See brw_blorp_blit_program).
 *
 * It can only translate between W and Y tiling, so new_tiling and old_tiling
 * are booleans where true represents W tiling and false represents Y tiling.
 */

> +
> +static inline nir_ssa_def *
> +blorp_nir_retile_y_to_w(nir_builder *b, nir_ssa_def *pos)
> +{
> +   assert(pos->num_components == 2);
> +   nir_ssa_def *x_Y = nir_channel(b, pos, 0);
> +   nir_ssa_def *y_Y = nir_channel(b, pos, 1);
> +
> +   /* Given X and Y coordinates that describe an address using Y tiling,
> +    * translate to the X and Y coordinates that describe the same address
> +    * using W tiling.
> +    *
> +    * If we break down the low order bits of X and Y, using a
> +    * single letter to represent each low-order bit:
> +    *
> +    *   X = A << 7 | 0bBCDEFGH
> +    *   Y = J << 5 | 0bKLMNP                                       (1)
> +    *
> +    * Then we can apply the Y tiling formula to see the memory offset being
> +    * addressed:
> +    *
> +    *   offset = (J * tile_pitch + A) << 12 | 0bBCDKLMNPEFGH       (2)
> +    *
> +    * If we apply the W detiling formula to this memory location, that the
> +    * corresponding X' and Y' coordinates are:
> +    *
> +    *   X' = A << 6 | 0bBCDPFH                                     (3)
> +    *   Y' = J << 6 | 0bKLMNEG
> +    *
> +    * Combining (1) and (3), we see that to transform (X, Y) to (X', Y'),
> +    * we need to make the following computation:
> +    *
> +    *   X' = (X & ~0b1011) >> 1 | (Y & 0b1) << 2 | X & 0b1         (4)
> +    *   Y' = (Y & ~0b1) << 1 | (X & 0b1000) >> 2 | (X & 0b10) >> 1
> +    */
> +   nir_ssa_def *x_W = nir_imm_int(b, 0);
> +   x_W = nir_mask_shift_or(b, x_W, x_Y, 0xfffffff4, -1);
> +   x_W = nir_mask_shift_or(b, x_W, y_Y, 0x1, 2);
> +   x_W = nir_mask_shift_or(b, x_W, x_Y, 0x1, 0);
> +
> +   nir_ssa_def *y_W = nir_imm_int(b, 0);
> +   y_W = nir_mask_shift_or(b, y_W, y_Y, 0xfffffffe, 1);
> +   y_W = nir_mask_shift_or(b, y_W, x_Y, 0x8, -2);
> +   y_W = nir_mask_shift_or(b, y_W, x_Y, 0x2, -1);
> +
> +   return nir_vec2(b, x_W, y_W);
> +}
> +
> +static inline nir_ssa_def *
> +blorp_nir_retile_w_to_y(nir_builder *b, nir_ssa_def *pos)
> +{
> +   assert(pos->num_components == 2);
> +   nir_ssa_def *x_W = nir_channel(b, pos, 0);
> +   nir_ssa_def *y_W = nir_channel(b, pos, 1);
> +
> +   /* Applying the same logic as above, but in reverse, we obtain the
> +    * formulas:
> +    *
> +    * X' = (X & ~0b101) << 1 | (Y & 0b10) << 2 | (Y & 0b1) << 1 | X & 0b1
> +    * Y' = (Y & ~0b11) >> 1 | (X & 0b100) >> 2
> +    */
> +   nir_ssa_def *x_Y = nir_imm_int(b, 0);
> +   x_Y = nir_mask_shift_or(b, x_Y, x_W, 0xfffffffa, 1);
> +   x_Y = nir_mask_shift_or(b, x_Y, y_W, 0x2, 2);
> +   x_Y = nir_mask_shift_or(b, x_Y, y_W, 0x1, 1);
> +   x_Y = nir_mask_shift_or(b, x_Y, x_W, 0x1, 0);
> +
> +   nir_ssa_def *y_Y = nir_imm_int(b, 0);
> +   y_Y = nir_mask_shift_or(b, y_Y, y_W, 0xfffffffc, -1);
> +   y_Y = nir_mask_shift_or(b, y_Y, x_W, 0x4, -2);
> +
> +   return nir_vec2(b, x_Y, y_Y);
> +}
> +
>  /**
>   * Generator for WM programs used in BLORP blits.
>   *
> @@ -786,7 +878,12 @@ brw_blorp_build_nir_shader(struct brw_context *brw,
>     if (rt_tiled_w != key->dst_tiled_w ||
>         key->rt_samples != key->dst_samples ||
>         key->rt_layout != key->dst_layout) {
> -      goto fail;
> +      if (key->rt_samples != key->dst_samples ||
> +          key->rt_layout != key->dst_layout ||
> +          key->rt_samples != 0)

I think we need to allow rt_samples == 1 also, right? Single sampled can
have either zero or one samples in miptree.

> +         goto fail;
> +      if (rt_tiled_w != key->dst_tiled_w)
> +         dst_pos = blorp_nir_retile_y_to_w(&b, dst_pos);
>     }
>  
>     /* Now (X, Y, S) = decode_msaa(dst_samples, detile(dst_tiling, offset)).
> @@ -832,7 +929,13 @@ brw_blorp_build_nir_shader(struct brw_context *brw,
>             key->tex_samples != key->src_samples ||
>             key->tex_layout != key->src_layout) &&
>            !key->bilinear_filter) {
> -         goto fail;
> +         if (key->tex_samples != key->src_samples ||
> +             key->tex_layout != key->src_layout ||
> +             key->tex_samples != 0)

Same here. Otherwise:

Reviewed-by: Topi Pohjolainen <topi.pohjolainen at intel.com>

> +            goto fail;
> +
> +         if (tex_tiled_w != key->src_tiled_w)
> +            src_pos = blorp_nir_retile_w_to_y(&b, src_pos);
>        }
>  
>        if (key->bilinear_filter) {
> -- 
> 2.5.0.400.gff86faf
> 
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