gallium: Add PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT

Add PIPE_CAP to determine if the GL extension
'GL_ARB_framebuffer_no_attachments' shall be
supported.

The driver is required to support 'PIPE_FORMAT_NONE'
via its 'is_format_supported()' callback in order
to determine the MSAA modes the hardware supports so
that values requested from the application using
'GL_ARB_framebuffer_no_attachments' may be quantized
to what the hardware expects.

V.2:
 Fix doc for a more detailed description of the PIPE_CAP
 and the corresponding GL constant.

V.3:
 Renamed and repurposed once again.

V.4:
 Remove CAP from cap_mapping array.

[airlied: fix damaged whitespace]

Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/gallium/docs/source/screen.rst

@@ -323,6 +323,14 @@ The integer capabilities:
 * ``PIPE_CAP_PCI_BUS``: Return the PCI bus number.
 * ``PIPE_CAP_PCI_DEVICE``: Return the PCI device number.
 * ``PIPE_CAP_PCI_FUNCTION``: Return the PCI function number.
+* ``PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT``:
+  If non-zero, rendering to framebuffers with no surface attachments
+  is supported. The context->is_format_supported function will be expected
+  to be implemented with PIPE_FORMAT_NONE yeilding the MSAA modes the hardware
+  supports. N.B., The maximum number of layers supported for rasterizing a
+  primitive on a layer is obtained from ``PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS``
+  even though it can be larger than the number of layers supported by either
+  rendering or textures.
 
 
 .. _pipe_capf:

src/gallium/drivers/freedreno/freedreno_screen.c

@@ -255,6 +255,7 @@ fd_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 	case PIPE_CAP_INVALIDATE_BUFFER:
 	case PIPE_CAP_GENERATE_MIPMAP:
 	case PIPE_CAP_SURFACE_REINTERPRET_BLOCKS:
+	case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
 		return 0;
 
 	case PIPE_CAP_MAX_VIEWPORTS:

src/gallium/drivers/i915/i915_screen.c

@@ -269,6 +269,7 @@ i915_get_param(struct pipe_screen *screen, enum pipe_cap cap)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
 
    case PIPE_CAP_MAX_DUAL_SOURCE_RENDER_TARGETS:

src/gallium/drivers/ilo/ilo_screen.c

@@ -498,6 +498,7 @@ ilo_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/llvmpipe/lp_screen.c

@@ -319,6 +319,7 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
    }
    /* should only get here on unhandled cases */

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

@@ -192,6 +192,7 @@ nv30_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

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

@@ -245,6 +245,7 @@ nv50_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

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

@@ -251,6 +251,7 @@ nvc0_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/r300/r300_screen.c

@@ -214,6 +214,7 @@ static int r300_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
         case PIPE_CAP_SURFACE_REINTERPRET_BLOCKS:
         case PIPE_CAP_QUERY_BUFFER_OBJECT:
         case PIPE_CAP_QUERY_MEMORY_INFO:
+        case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
             return 0;
 
         /* SWTCL-only features. */

src/gallium/drivers/r600/r600_pipe.c

@@ -364,6 +364,7 @@ static int r600_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 	case PIPE_CAP_GENERATE_MIPMAP:
 	case PIPE_CAP_STRING_MARKER:
 	case PIPE_CAP_QUERY_BUFFER_OBJECT:
+	case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
 		return 0;
 
 	case PIPE_CAP_MAX_SHADER_PATCH_VARYINGS:

src/gallium/drivers/radeonsi/si_pipe.c

@@ -356,6 +356,7 @@ static int si_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 	case PIPE_CAP_GENERATE_MIPMAP:
 	case PIPE_CAP_STRING_MARKER:
 	case PIPE_CAP_QUERY_BUFFER_OBJECT:
+	case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
 		return 0;
 
 	case PIPE_CAP_MAX_SHADER_PATCH_VARYINGS:

src/gallium/drivers/softpipe/sp_screen.c

@@ -270,6 +270,7 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
    }
    /* should only get here on unhandled cases */

src/gallium/drivers/svga/svga_screen.c

@@ -404,6 +404,7 @@ svga_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL:
    case PIPE_CAP_BUFFER_SAMPLER_VIEW_RGBA_ONLY:
    case PIPE_CAP_QUERY_BUFFER_OBJECT:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
    }
 

src/gallium/drivers/vc4/vc4_screen.c

@@ -207,6 +207,7 @@ vc4_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
         case PIPE_CAP_PCI_BUS:
         case PIPE_CAP_PCI_DEVICE:
         case PIPE_CAP_PCI_FUNCTION:
+        case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
                 return 0;
 
                 /* Stream output. */

src/gallium/drivers/virgl/virgl_screen.c

@@ -239,6 +239,7 @@ virgl_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_PCI_BUS:
    case PIPE_CAP_PCI_DEVICE:
    case PIPE_CAP_PCI_FUNCTION:
+   case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
       return 0;
    case PIPE_CAP_VENDOR_ID:
       return 0x1af4;

src/gallium/include/pipe/p_defines.h

@@ -690,6 +690,7 @@ enum pipe_cap
    PIPE_CAP_PCI_BUS,
    PIPE_CAP_PCI_DEVICE,
    PIPE_CAP_PCI_FUNCTION,
+   PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT,
 };
 
 #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)