[Mesa-dev] [PATCH 3/3] r600g: handle unbind of constant buffers

[Keith Whitwell]

Statetrackers can unbind a constant buffer slot by calling

   pipe->set_constant_buffer(pipe, shader, slot, NULL)

The driver should unbind the buffer and potentially allow its storage
to be released.
---
 src/gallium/drivers/r600/r600_state.c |   20 ++++++++++++++++----
 1 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/r600/r600_state.c b/src/gallium/drivers/r600/r600_state.c
index 2c0a200..b5ae187 100644
--- a/src/gallium/drivers/r600/r600_state.c
+++ b/src/gallium/drivers/r600/r600_state.c
@@ -1160,28 +1160,40 @@ static void r600_set_constant_buffer(struct pipe_context *ctx, uint shader, uint
 {
 	struct r600_pipe_context *rctx = (struct r600_pipe_context *)ctx;
 	struct r600_resource *rbuffer = (struct r600_resource*)buffer;
+	unsigned width = 0;
+	unsigned offset = 0;
+	struct r600_bo *bo = NULL;
+	
+	/* Note that the state tracker can unbind constant buffers by
+	 * passing NULL here.
+	 */
+	if (buffer != NULL) {
+		width = buffer->width0;
+		offset = r600_bo_offset(rbuffer->bo);
+		bo = rbuffer->bo;
+	}
 
 	switch (shader) {
 	case PIPE_SHADER_VERTEX:
 		rctx->vs_const_buffer.nregs = 0;
 		r600_pipe_state_add_reg(&rctx->vs_const_buffer,
 					R_028180_ALU_CONST_BUFFER_SIZE_VS_0,
-					ALIGN_DIVUP(buffer->width0 >> 4, 16),
+					ALIGN_DIVUP(width >> 4, 16),
 					0xFFFFFFFF, NULL);
 		r600_pipe_state_add_reg(&rctx->vs_const_buffer,
 					R_028980_ALU_CONST_CACHE_VS_0,
-					r600_bo_offset(rbuffer->bo) >> 8, 0xFFFFFFFF, rbuffer->bo);
+					offset >> 8, 0xFFFFFFFF, bo);
 		r600_context_pipe_state_set(&rctx->ctx, &rctx->vs_const_buffer);
 		break;
 	case PIPE_SHADER_FRAGMENT:
 		rctx->ps_const_buffer.nregs = 0;
 		r600_pipe_state_add_reg(&rctx->ps_const_buffer,
 					R_028140_ALU_CONST_BUFFER_SIZE_PS_0,
-					ALIGN_DIVUP(buffer->width0 >> 4, 16),
+					ALIGN_DIVUP(width >> 4, 16),
 					0xFFFFFFFF, NULL);
 		r600_pipe_state_add_reg(&rctx->ps_const_buffer,
 					R_028940_ALU_CONST_CACHE_PS_0,
-					r600_bo_offset(rbuffer->bo) >> 8, 0xFFFFFFFF, rbuffer->bo);
+					offset >> 8, 0xFFFFFFFF, bo);
 		r600_context_pipe_state_set(&rctx->ctx, &rctx->ps_const_buffer);
 		break;
 	default:
-- 
1.7.1