vc4: Add a flag in the screen to track control flow support.

For now it's still always false, but I need it in place for kernel
backwards compat support as I extend the backend for control flow.

3 files changed, 14 insertions, 1 deletions

diff --git a/src/gallium/drivers/vc4/vc4_program.c b/src/gallium/drivers/vc4/vc4_program.c
index 0a231b2f6e8..dec14453203 100644
--- a/src/gallium/drivers/vc4/vc4_program.c
+++ b/src/gallium/drivers/vc4/vc4_program.c
@@ -1765,6 +1765,7 @@ vc4_shader_ntq(struct vc4_context *vc4, enum qstage stage,
 {
         struct vc4_compile *c = qir_compile_init();
 
+        c->vc4 = vc4;
         c->stage = stage;
         c->shader_state = &key->shader_state->base;
         c->program_id = key->shader_state->program_id;
diff --git a/src/gallium/drivers/vc4/vc4_screen.c b/src/gallium/drivers/vc4/vc4_screen.c
index 609dc913655..f60500ddec3 100644
--- a/src/gallium/drivers/vc4/vc4_screen.c
+++ b/src/gallium/drivers/vc4/vc4_screen.c
@@ -329,8 +329,10 @@ vc4_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
         case PIPE_SHADER_CAP_MAX_TEX_INSTRUCTIONS:
         case PIPE_SHADER_CAP_MAX_TEX_INDIRECTIONS:
                 return 16384;
+
         case PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH:
-                return 0;
+                return vc4_screen(pscreen)->has_control_flow;
+
         case PIPE_SHADER_CAP_MAX_INPUTS:
                 if (shader == PIPE_SHADER_FRAGMENT)
                         return 8;
@@ -494,6 +496,12 @@ vc4_screen_is_format_supported(struct pipe_screen *pscreen,
         return retval == usage;
 }
 
+static bool
+vc4_supports_branches(struct vc4_screen *screen)
+{
+        return false;
+}
+
 struct pipe_screen *
 vc4_screen_create(int fd)
 {
@@ -512,6 +520,9 @@ vc4_screen_create(int fd)
         screen->fd = fd;
         list_inithead(&screen->bo_cache.time_list);
 
+        if (vc4_supports_branches(screen))
+                screen->has_control_flow = true;
+
         vc4_fence_init(screen);
 
         vc4_debug = debug_get_option_vc4_debug();
diff --git a/src/gallium/drivers/vc4/vc4_screen.h b/src/gallium/drivers/vc4/vc4_screen.h
index 03f76b257e3..6cecca63bc4 100644
--- a/src/gallium/drivers/vc4/vc4_screen.h
+++ b/src/gallium/drivers/vc4/vc4_screen.h
@@ -75,6 +75,7 @@ struct vc4_screen {
 
         uint32_t bo_size;
         uint32_t bo_count;
+        bool has_control_flow;
 };
 
 static inline struct vc4_screen *