gallium: add PIPE_CAP_MAX_COMBINED_SHADER_BUFFERS

This gets rid of a r600 specific hack in the state-tracker, and prepares
for other drivers to be able to use hw-atomics.

While we're at it, clean up some indentation in the various drivers.

Signed-off-by: Erik Faye-Lund <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>
Reviewed-by: Gurchetan Singh <[email protected]>

5 files changed, 13 insertions, 2 deletions

diff --git a/src/gallium/auxiliary/util/u_screen.c b/src/gallium/auxiliary/util/u_screen.c
index d19d604e0c5..7a37fe78468 100644
--- a/src/gallium/auxiliary/util/u_screen.c
+++ b/src/gallium/auxiliary/util/u_screen.c
@@ -304,6 +304,7 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
    case PIPE_CAP_MAX_CONSERVATIVE_RASTER_SUBPIXEL_PRECISION_BIAS:
    case PIPE_CAP_CONSERVATIVE_RASTER_POST_DEPTH_COVERAGE:
    case PIPE_CAP_PROGRAMMABLE_SAMPLE_LOCATIONS:
+   case PIPE_CAP_MAX_COMBINED_SHADER_BUFFERS:
       return 0;
 
    case PIPE_CAP_MAX_GS_INVOCATIONS:
diff --git a/src/gallium/docs/source/screen.rst b/src/gallium/docs/source/screen.rst
index 485248261df..d589bad30ef 100644
--- a/src/gallium/docs/source/screen.rst
+++ b/src/gallium/docs/source/screen.rst
@@ -458,6 +458,9 @@ subpixel precision bias in bits during conservative rasterization.
   TGSI_PROPERTY_GS_INVOCATIONS.
 * ``PIPE_CAP_MAX_SHADER_BUFFER_SIZE``: Maximum supported size for binding
   with set_shader_buffers.
+* ``PIPE_CAP_MAX_COMBINED_SHADER_BUFFERS``: Maximum total number of shader
+  buffers. A value of 0 means the sum of all per-shader stage maximums (see
+  ``PIPE_SHADER_CAP_MAX_SHADER_BUFFERS``).
 
 .. _pipe_capf:
 
diff --git a/src/gallium/drivers/r600/r600_pipe.c b/src/gallium/drivers/r600/r600_pipe.c
index bcc72c8b698..f1e80a8f827 100644
--- a/src/gallium/drivers/r600/r600_pipe.c
+++ b/src/gallium/drivers/r600/r600_pipe.c
@@ -380,8 +380,12 @@ static int r600_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 
 	case PIPE_CAP_MAX_GS_INVOCATIONS:
 		return 32;
+
+	/* shader buffer objects */
 	case PIPE_CAP_MAX_SHADER_BUFFER_SIZE:
 		return 1 << 27;
+	case PIPE_CAP_MAX_COMBINED_SHADER_BUFFERS:
+		return 8;
 
 	/* Unsupported features. */
 	case PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT:
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index 3bc908d1a0e..b7c7d8fcbd5 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -818,6 +818,7 @@ enum pipe_cap
    PIPE_CAP_MAX_GS_INVOCATIONS,
    PIPE_CAP_MAX_SHADER_BUFFER_SIZE,
    PIPE_CAP_TEXTURE_MIRROR_CLAMP_TO_EDGE,
+   PIPE_CAP_MAX_COMBINED_SHADER_BUFFERS,
 };
 
 /**
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 9ecdd26edda..0fc13d0dd24 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -470,8 +470,10 @@ void st_init_limits(struct pipe_screen *screen,
    c->ShaderStorageBufferOffsetAlignment =
       screen->get_param(screen, PIPE_CAP_SHADER_BUFFER_OFFSET_ALIGNMENT);
    if (c->ShaderStorageBufferOffsetAlignment) {
-      /* for hw atomic counters leaves these at default for now */
-      if (ssbo_atomic) {
+      c->MaxCombinedShaderStorageBlocks =
+         MIN2(screen->get_param(screen, PIPE_CAP_MAX_COMBINED_SHADER_BUFFERS),
+              MAX_COMBINED_SHADER_STORAGE_BUFFERS);
+      if (!c->MaxCombinedShaderStorageBlocks) {
          c->MaxCombinedShaderStorageBlocks =
             c->Program[MESA_SHADER_VERTEX].MaxShaderStorageBlocks +
             c->Program[MESA_SHADER_TESS_CTRL].MaxShaderStorageBlocks +