panfrost: Suppress Bifrost prefetching

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7408>

diff --git a/src/gallium/drivers/panfrost/pan_cmdstream.c b/src/gallium/drivers/panfrost/pan_cmdstream.c
index ce55bce..645047f 100644 (file)
--- a/src/gallium/drivers/panfrost/pan_cmdstream.c
+++ b/src/gallium/drivers/panfrost/pan_cmdstream.c
@@ -1097,13 +1097,15 @@ panfrost_emit_vertex_data(struct panfrost_batch *batch,
                           mali_ptr *buffers)
 {
         struct panfrost_context *ctx = batch->ctx;
+        struct panfrost_device *dev = pan_device(ctx->base.screen);
+        bool is_bifrost = !!(dev->quirks & IS_BIFROST);
         struct panfrost_vertex_state *so = ctx->vertex;
         struct panfrost_shader_state *vs = panfrost_get_shader_state(ctx, PIPE_SHADER_VERTEX);
 
         /* Worst case: everything is NPOT, which is only possible if instancing
          * is enabled. Otherwise single record is gauranteed */
         struct panfrost_ptr S = panfrost_pool_alloc_aligned(&batch->pool,
-                        MALI_ATTRIBUTE_BUFFER_LENGTH * vs->attribute_count *
+                        MALI_ATTRIBUTE_BUFFER_LENGTH * (vs->attribute_count + 1) *
                         (ctx->instance_count > 1 ? 2 : 1),
                         MALI_ATTRIBUTE_BUFFER_LENGTH * 2);
 
@@ -1114,6 +1116,10 @@ panfrost_emit_vertex_data(struct panfrost_batch *batch,
         struct mali_attribute_buffer_packed *bufs =
                 (struct mali_attribute_buffer_packed *) S.cpu;
 
+        /* Determine (n + 1)'th index to suppress prefetch on Bifrost */
+        unsigned last = vs->attribute_count * ((ctx->instance_count > 1) ? 2 : 1);
+        memset(bufs + last, 0, sizeof(*bufs));
+
         struct mali_attribute_packed *out =
                 (struct mali_attribute_packed *) T.cpu;
 
@@ -1232,6 +1238,10 @@ panfrost_emit_vertex_data(struct panfrost_batch *batch,
                 }
         }
 
+        /* We need an empty attrib buf to stop the prefetching on Bifrost */
+        if (is_bifrost)
+                pan_pack(&bufs[k], ATTRIBUTE_BUFFER, cfg);
+
         /* Attribute addresses require 64-byte alignment, so let:
          *
          *      base' = base & ~63 = base - (base & 63)
@@ -1753,11 +1763,14 @@ panfrost_emit_varying_descriptor(struct panfrost_batch *batch,
 
         unsigned xfb_base = pan_xfb_base(present);
         struct panfrost_ptr T = panfrost_pool_alloc_aligned(&batch->pool,
-                        MALI_ATTRIBUTE_BUFFER_LENGTH * (xfb_base + ctx->streamout.num_targets),
+                        MALI_ATTRIBUTE_BUFFER_LENGTH * (xfb_base + ctx->streamout.num_targets + 1),
                         MALI_ATTRIBUTE_BUFFER_LENGTH * 2);
         struct mali_attribute_buffer_packed *varyings =
                 (struct mali_attribute_buffer_packed *) T.cpu;
 
+        /* Suppress prefetch on Bifrost */
+        memset(varyings + (xfb_base * ctx->streamout.num_targets), 0, sizeof(*varyings));
+
         /* Emit the stream out buffers */
 
         unsigned out_count = u_stream_outputs_for_vertices(ctx->active_prim,