r600g: Compute the correct wavefront size

1 files changed, 12 insertions, 2 deletions

diff --git a/src/gallium/drivers/r600/evergreen_compute.c b/src/gallium/drivers/r600/evergreen_compute.c
index 58d9b3c6b17..4d98ceaa821 100644
--- a/src/gallium/drivers/r600/evergreen_compute.c
+++ b/src/gallium/drivers/r600/evergreen_compute.c
@@ -454,8 +454,18 @@ static void evergreen_launch_grid(
   COMPUTE_DBG("PC: %i\n", pc);
   
   struct r600_context *ctx = (struct r600_context *)ctx_;
-  
-  evergreen_set_lds(ctx->cs_shader, 0, 0, 0);
+  unsigned num_waves;
+  unsigned num_pipes = ctx->screen->info.r600_max_pipes;
+  unsigned wave_divisor = (16 * num_pipes);
+
+  /* num_waves = ceil((tg_size.x * tg_size.y, tg_size.z) / (16 * num_pipes)) */
+  num_waves = (block_layout[0] * block_layout[1] * block_layout[2] + wave_divisor - 1) /
+              wave_divisor;
+
+  COMPUTE_DBG("Using %u pipes, there are %u wavefronts per thread block\n",
+              num_pipes, num_waves);
+
+  evergreen_set_lds(ctx->cs_shader, 0, 0, num_waves);
   evergreen_compute_upload_input(ctx_, block_layout, grid_layout, input);
   evergreen_direct_dispatch(ctx_, block_layout, grid_layout);
   compute_emit_cs(ctx);