gallium: add PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT

This avoids a serious r600g bug leading to a GPU hang.
The chances this bug will get fixed are pretty low now.

I deeply regret listening to others and not pushing this patch, leaving
other users with a GPU-crashing driver. Yes, it should be fixed
in the compiler and it's ugly, but users couldn't care less about that.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86720

Cc: 11.0 10.6 <[email protected]>
Reviewed-by: Brian Paul <[email protected]>

11 files changed, 32 insertions, 0 deletions

diff --git a/src/gallium/drivers/freedreno/freedreno_screen.c b/src/gallium/drivers/freedreno/freedreno_screen.c
index f85e4586413..50d140fe903 100644
--- a/src/gallium/drivers/freedreno/freedreno_screen.c
+++ b/src/gallium/drivers/freedreno/freedreno_screen.c
@@ -412,6 +412,8 @@ fd_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
 		return 16;
 	case PIPE_SHADER_CAP_PREFERRED_IR:
 		return PIPE_SHADER_IR_TGSI;
+	case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+		return 32;
 	}
 	debug_printf("unknown shader param %d\n", param);
 	return 0;
diff --git a/src/gallium/drivers/i915/i915_screen.c b/src/gallium/drivers/i915/i915_screen.c
index c91408d3d9b..5812af626cb 100644
--- a/src/gallium/drivers/i915/i915_screen.c
+++ b/src/gallium/drivers/i915/i915_screen.c
@@ -167,6 +167,8 @@ i915_get_shader_param(struct pipe_screen *screen, unsigned shader, enum pipe_sha
       case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
       case PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE:
          return 0;
+      case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+         return 32;
       default:
          debug_printf("%s: Unknown cap %u.\n", __FUNCTION__, cap);
          return 0;
diff --git a/src/gallium/drivers/ilo/ilo_screen.c b/src/gallium/drivers/ilo/ilo_screen.c
index acf688fc02c..e1a7dc56685 100644
--- a/src/gallium/drivers/ilo/ilo_screen.c
+++ b/src/gallium/drivers/ilo/ilo_screen.c
@@ -138,6 +138,8 @@ ilo_get_shader_param(struct pipe_screen *screen, unsigned shader,
       return PIPE_SHADER_IR_TGSI;
    case PIPE_SHADER_CAP_TGSI_SQRT_SUPPORTED:
       return 1;
+   case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+      return 32;
 
    default:
       return 0;
diff --git a/src/gallium/drivers/nouveau/nv30/nv30_screen.c b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
index d4cf143b9a3..03301649e38 100644
--- a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
+++ b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
@@ -264,6 +264,8 @@ nv30_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
       case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
       case PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE:
          return 0;
+      case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+         return 32;
       default:
          debug_printf("unknown vertex shader param %d\n", param);
          return 0;
@@ -305,6 +307,8 @@ nv30_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
       case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
       case PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE:
          return 0;
+      case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+         return 32;
       default:
          debug_printf("unknown fragment shader param %d\n", param);
          return 0;
diff --git a/src/gallium/drivers/nouveau/nv50/nv50_screen.c b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
index a4431f20e14..ec51d00f266 100644
--- a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
+++ b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
@@ -300,6 +300,8 @@ nv50_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
    case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
    case PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE:
       return 0;
+   case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+      return 32;
    default:
       NOUVEAU_ERR("unknown PIPE_SHADER_CAP %d\n", param);
       return 0;
diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
index d34c8a2b07b..af8e5f72670 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
@@ -313,6 +313,8 @@ nvc0_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
       return 16; /* would be 32 in linked (OpenGL-style) mode */
    case PIPE_SHADER_CAP_MAX_SAMPLER_VIEWS:
       return 16; /* XXX not sure if more are really safe */
+   case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+      return 32;
    default:
       NOUVEAU_ERR("unknown PIPE_SHADER_CAP %d\n", param);
       return 0;
diff --git a/src/gallium/drivers/r300/r300_screen.c b/src/gallium/drivers/r300/r300_screen.c
index c1c522b0a3a..a576abdfaf2 100644
--- a/src/gallium/drivers/r300/r300_screen.c
+++ b/src/gallium/drivers/r300/r300_screen.c
@@ -303,6 +303,8 @@ static int r300_get_shader_param(struct pipe_screen *pscreen, unsigned shader, e
         case PIPE_SHADER_CAP_TGSI_DFRACEXP_DLDEXP_SUPPORTED:
         case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
             return 0;
+        case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+            return 32;
         case PIPE_SHADER_CAP_PREFERRED_IR:
             return PIPE_SHADER_IR_TGSI;
         }
@@ -359,6 +361,8 @@ static int r300_get_shader_param(struct pipe_screen *pscreen, unsigned shader, e
         case PIPE_SHADER_CAP_TGSI_DFRACEXP_DLDEXP_SUPPORTED:
         case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
             return 0;
+        case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+            return 32;
         case PIPE_SHADER_CAP_PREFERRED_IR:
             return PIPE_SHADER_IR_TGSI;
         }
diff --git a/src/gallium/drivers/r600/r600_pipe.c b/src/gallium/drivers/r600/r600_pipe.c
index 75de553be2b..9a97de9965e 100644
--- a/src/gallium/drivers/r600/r600_pipe.c
+++ b/src/gallium/drivers/r600/r600_pipe.c
@@ -511,6 +511,12 @@ static int r600_get_shader_param(struct pipe_screen* pscreen, unsigned shader, e
 	case PIPE_SHADER_CAP_TGSI_DFRACEXP_DLDEXP_SUPPORTED:
 	case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
 		return 0;
+	case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+		/* due to a bug in the shader compiler, some loops hang
+		 * if they are not unrolled, see:
+		 *    https://bugs.freedesktop.org/show_bug.cgi?id=86720
+		 */
+		return 255;
 	}
 	return 0;
 }
diff --git a/src/gallium/drivers/radeonsi/si_pipe.c b/src/gallium/drivers/radeonsi/si_pipe.c
index c084f03cd25..5f910c95ef3 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.c
+++ b/src/gallium/drivers/radeonsi/si_pipe.c
@@ -508,6 +508,8 @@ static int si_get_shader_param(struct pipe_screen* pscreen, unsigned shader, enu
 	case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
 	case PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE:
 		return 1;
+	case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+		return 32;
 	}
 	return 0;
 }
diff --git a/src/gallium/drivers/svga/svga_screen.c b/src/gallium/drivers/svga/svga_screen.c
index 9bf661fab8c..17b042e7d95 100644
--- a/src/gallium/drivers/svga/svga_screen.c
+++ b/src/gallium/drivers/svga/svga_screen.c
@@ -456,6 +456,8 @@ vgpu9_get_shader_param(struct pipe_screen *screen, unsigned shader,
       case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
       case PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE:
          return 0;
+      case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+         return 32;
       }
       /* If we get here, we failed to handle a cap above */
       debug_printf("Unexpected fragment shader query %u\n", param);
@@ -512,6 +514,8 @@ vgpu9_get_shader_param(struct pipe_screen *screen, unsigned shader,
       case PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED:
       case PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE:
          return 0;
+      case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+         return 32;
       }
       /* If we get here, we failed to handle a cap above */
       debug_printf("Unexpected vertex shader query %u\n", param);
diff --git a/src/gallium/drivers/vc4/vc4_screen.c b/src/gallium/drivers/vc4/vc4_screen.c
index 3b12464a2f6..774ec095652 100644
--- a/src/gallium/drivers/vc4/vc4_screen.c
+++ b/src/gallium/drivers/vc4/vc4_screen.c
@@ -337,6 +337,8 @@ vc4_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
                 return VC4_MAX_TEXTURE_SAMPLERS;
         case PIPE_SHADER_CAP_PREFERRED_IR:
                 return PIPE_SHADER_IR_TGSI;
+	case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
+		return 32;
         default:
                 fprintf(stderr, "unknown shader param %d\n", param);
                 return 0;