gallium: Add MULTISAMPLE_Z_RESOLVE cap

Resolving a multisampled depth texture into
a single sampled texture is supported on >= SM4.1
hw. It is possible some previous hw support it.

The ability was tested on radeonsi and nvc0.
Apparently is is also supported for radeon >= r700.

This patch adds the MULTISAMPLE_Z_RESOLVE cap and
add it to the drivers. It is advertised for drivers
for which it is sure the ability is supported.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Axel Davy <axel.davy@ens.fr>

src/gallium/docs/source/screen.rst

@@ -243,6 +243,9 @@ The integer capabilities:
   this, at least BASEVERTEX should be exposed separately too).
 * ``PIPE_CAP_POLYGON_OFFSET_CLAMP``: If true, the driver implements support
   for ``pipe_rasterizer_state::offset_clamp``.
+* ``PIPE_CAP_MULTISAMPLE_Z_RESOLVE``: Whether the driver supports blitting
+  a multisampled depth buffer into a single-sampled texture (or depth buffer).
+  Only the first sampled should be copied.
 
 
 .. _pipe_capf:

src/gallium/drivers/freedreno/freedreno_screen.c

@@ -230,6 +230,7 @@ fd_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 	case PIPE_CAP_CLIP_HALFZ:
 	case PIPE_CAP_VERTEXID_NOBASE:
 	case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+	case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
 		return 0;
 
 	case PIPE_CAP_MAX_VIEWPORTS:

src/gallium/drivers/i915/i915_screen.c

@@ -228,6 +228,7 @@ i915_get_param(struct pipe_screen *screen, enum pipe_cap cap)
    case PIPE_CAP_CLIP_HALFZ:
    case PIPE_CAP_VERTEXID_NOBASE:
    case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
       return 0;
 
    case PIPE_CAP_MAX_DUAL_SOURCE_RENDER_TARGETS:

src/gallium/drivers/ilo/ilo_screen.c

@@ -470,6 +470,7 @@ ilo_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
    case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
    case PIPE_CAP_SAMPLER_VIEW_TARGET:
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/llvmpipe/lp_screen.c

@@ -287,6 +287,8 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
       return 0;
    case PIPE_CAP_POLYGON_OFFSET_CLAMP:
       return 1;
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
+      return 0;
    }
    /* should only get here on unhandled cases */
    debug_printf("Unexpected PIPE_CAP %d query\n", param);

src/gallium/drivers/nouveau/nv30/nv30_screen.c

@@ -159,6 +159,7 @@ nv30_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_CLIP_HALFZ:
    case PIPE_CAP_VERTEXID_NOBASE:
    case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/nouveau/nv50/nv50_screen.c

@@ -207,6 +207,7 @@ nv50_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_COMPUTE:
    case PIPE_CAP_DRAW_INDIRECT:
    case PIPE_CAP_VERTEXID_NOBASE:
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE: /* potentially supported on some hw */
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/nouveau/nvc0/nvc0_screen.c

@@ -173,6 +173,7 @@ nvc0_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_SAMPLER_VIEW_TARGET:
    case PIPE_CAP_CLIP_HALFZ:
    case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
       return 1;
    case PIPE_CAP_SEAMLESS_CUBE_MAP_PER_TEXTURE:
       return (class_3d >= NVE4_3D_CLASS) ? 1 : 0;

src/gallium/drivers/r300/r300_screen.c

@@ -183,6 +183,7 @@ static int r300_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
         case PIPE_CAP_SAMPLER_VIEW_TARGET:
         case PIPE_CAP_VERTEXID_NOBASE:
         case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+        case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
             return 0;
 
         /* SWTCL-only features. */

src/gallium/drivers/r600/r600_pipe.c

@@ -401,6 +401,8 @@ static int r600_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 		return rscreen->b.info.vram_size >> 20;
 	case PIPE_CAP_UMA:
 		return 0;
+	case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
+		return rscreen->b.chip_class >= R700;
 	}
 	return 0;
 }

src/gallium/drivers/radeonsi/si_pipe.c

@@ -229,6 +229,7 @@ static int si_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 	case PIPE_CAP_CLIP_HALFZ:
 	case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
 	case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+	case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
 		return 1;
 
 	case PIPE_CAP_TEXTURE_MULTISAMPLE:

src/gallium/drivers/softpipe/sp_screen.c

@@ -235,6 +235,8 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
       return 0;
    case PIPE_CAP_POLYGON_OFFSET_CLAMP:
       return 0;
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
+      return 0;
    }
    /* should only get here on unhandled cases */
    debug_printf("Unexpected PIPE_CAP %d query\n", param);

src/gallium/drivers/svga/svga_screen.c

@@ -284,6 +284,7 @@ svga_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_CLIP_HALFZ:
    case PIPE_CAP_VERTEXID_NOBASE:
    case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+   case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
       return 0;
    case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:
       return 64;

src/gallium/drivers/vc4/vc4_screen.c

@@ -171,6 +171,7 @@ vc4_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
         case PIPE_CAP_CLIP_HALFZ:
         case PIPE_CAP_VERTEXID_NOBASE:
         case PIPE_CAP_POLYGON_OFFSET_CLAMP:
+        case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
                 return 0;
 
                 /* Stream output. */

src/gallium/include/pipe/p_defines.h

@@ -574,6 +574,7 @@ enum pipe_cap {
    PIPE_CAP_CLIP_HALFZ = 111,
    PIPE_CAP_VERTEXID_NOBASE = 112,
    PIPE_CAP_POLYGON_OFFSET_CLAMP = 113,
+   PIPE_CAP_MULTISAMPLE_Z_RESOLVE = 114,
 };
 
 #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)