We previously only did a buffer readback if it was dirty and we were
about to do a read-transfer. Now also do a readback for write-transfers
when not overwriting the entire buffer. We have to do that to keep the
guest/host buffers synchronized in order to support host-side buffer
copies with SVGA3dCmdDXBufferCopy.
Tested with full piglit run.
---
src/gallium/drivers/svga/svga_resource_buffer.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/src/gallium/drivers/svga/svga_resource_buffer.c
b/src/gallium/drivers/svga/svga_resource_buffer.c
index 9ecb975..192425b 100644
--- a/src/gallium/drivers/svga/svga_resource_buffer.c
+++ b/src/gallium/drivers/svga/svga_resource_buffer.c
@@ -95,11 +95,16 @@ svga_buffer_transfer_map(struct pipe_context *pipe,
transfer->usage = usage;
transfer->box = *box;
- if ((usage & PIPE_TRANSFER_READ) && sbuf->dirty) {
- /* Only need to test for vgpu10 since only vgpu10 features (streamout,
- * buffer copy) can modify buffers on the device.
+ if (sbuf->dirty) {
+ /* dirty means the host copy of the resource was modified, probably
+ * either with stream output or a buffer copy (only possible with vgpu10.
+ * We may need to do a readback to update the guest copy.
*/
- if (svga_have_vgpu10(svga)) {
+ if (svga_have_vgpu10(svga) &&
+ ((usage & PIPE_TRANSFER_READ) != 0 ||
+ ((usage & PIPE_TRANSFER_WRITE) != 0 &&
+ (box->x != 0 || box->width != resource->width0)))) {
+ /* mapping for read, or writing a subset of the resource */
enum pipe_error ret;
assert(sbuf->handle);
ret = SVGA3D_vgpu10_ReadbackSubResource(svga->swc, sbuf->handle, 0);
@@ -112,9 +117,9 @@ svga_buffer_transfer_map(struct pipe_context *pipe,
svga->hud.num_readbacks++;
svga_context_finish(svga);
-
- sbuf->dirty = FALSE;
}
+
+ sbuf->dirty = FALSE;
}
if (usage & PIPE_TRANSFER_WRITE) {
--
1.9.1
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