[Mesa-dev] [PATCH 1/2] radeonsi: fix UNSIGNED_BYTE index buffer fallback with non-zero start (v2)

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

start can only be non-zero with MultiDrawElements, which is unlikely
to occur with UNSIGNED_BYTE indices.

v2: Also fix the util_shorten_ubyte_elts_to_userptr call.
    Tested with the new piglit.

Cc: mesa-stable at lists.freedesktop.org
---
 src/gallium/drivers/radeonsi/si_state_draw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index d453309..b45ef87 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -1045,32 +1045,32 @@ void si_draw_vbo(struct pipe_context *ctx, const struct pipe_draw_info *info)
 		ib.offset = sctx->index_buffer.offset;
 
 		/* Translate or upload, if needed. */
 		/* 8-bit indices are supported on VI. */
 		if (sctx->b.chip_class <= CIK && ib.index_size == 1) {
 			struct pipe_resource *out_buffer = NULL;
 			unsigned out_offset, start, count, start_offset;
 			void *ptr;
 
 			si_get_draw_start_count(sctx, info, &start, &count);
-			start_offset = start * ib.index_size;
+			start_offset = start * 2;
 
 			u_upload_alloc(ctx->stream_uploader, start_offset,
                                        count * 2, 256,
 				       &out_offset, &out_buffer, &ptr);
 			if (!out_buffer) {
 				pipe_resource_reference(&ib.buffer, NULL);
 				return;
 			}
 
 			util_shorten_ubyte_elts_to_userptr(&sctx->b.b, &ib, 0,
-							   ib.offset + start_offset,
+							   ib.offset + start,
 							   count, ptr);
 
 			pipe_resource_reference(&ib.buffer, NULL);
 			ib.user_buffer = NULL;
 			ib.buffer = out_buffer;
 			/* info->start will be added by the drawing code */
 			ib.offset = out_offset - start_offset;
 			ib.index_size = 2;
 		} else if (ib.user_buffer && !ib.buffer) {
 			unsigned start, count, start_offset;
-- 
2.7.4