Nouveau - Feb 2015 - [PATCH 1/2] st/mesa: treat resource-less xfb buffers as if they weren't there

If a transform feedback buffer's size is 0, st_bufferobj_data doesn't
end up creating a buffer for it. There's no point in trying to write to
such a buffer, so just pretend as if it's not really there.

This fixes arb_gpu_shader5-xfb-streams-without-invocations on nvc0.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---
 src/mesa/state_tracker/st_cb_xformfb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mesa/state_tracker/st_cb_xformfb.c
b/src/mesa/state_tracker/st_cb_xformfb.c
index 8f75eda..a2bd86a 100644
--- a/src/mesa/state_tracker/st_cb_xformfb.c
+++ b/src/mesa/state_tracker/st_cb_xformfb.c
@@ -122,7 +122,7 @@ st_begin_transform_feedback(struct gl_context *ctx, GLenum
mode,
    for (i = 0; i < max_num_targets; i++) {
       struct st_buffer_object *bo = st_buffer_object(sobj->base.Buffers[i]);
 
-      if (bo) {
+      if (bo && bo->buffer) {
          /* Check whether we need to recreate the target. */
          if (!sobj->targets[i] ||
              sobj->targets[i] == sobj->draw_count ||
-- 
2.0.5

Tested with a modified xfb-streams test which outputs to streams 0, 2,
and 3.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---
 src/gallium/drivers/nouveau/nvc0/nvc0_shader_state.c | 9 ++++++++-
 src/gallium/drivers/nouveau/nvc0/nvc0_state.c        | 8 +++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_shader_state.c
b/src/gallium/drivers/nouveau/nvc0/nvc0_shader_state.c
index 1000d82..516b33b 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_shader_state.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_shader_state.c
@@ -252,7 +252,12 @@ nvc0_tfb_validate(struct nvc0_context *nvc0)
 
    for (b = 0; b < nvc0->num_tfbbufs; ++b) {
       struct nvc0_so_target *targ = nvc0_so_target(nvc0->tfbbuf[b]);
-      struct nv04_resource *buf = nv04_resource(targ->pipe.buffer);
+      struct nv04_resource *buf;
+
+      if (!targ) {
+         IMMED_NVC0(push, NVC0_3D(TFB_BUFFER_ENABLE(b)), 0);
+         continue;
+      }
 
       if (tfb)
          targ->stride = tfb->stride[b];
@@ -260,6 +265,8 @@ nvc0_tfb_validate(struct nvc0_context *nvc0)
       if (!(nvc0->tfbbuf_dirty & (1 << b)))
          continue;
 
+      buf = nv04_resource(targ->pipe.buffer);
+
       if (!targ->clean)
          nvc0_query_fifo_wait(push, targ->pq);
       BEGIN_NVC0(push, NVC0_3D(TFB_BUFFER_ENABLE(b)), 5);
diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_state.c
b/src/gallium/drivers/nouveau/nvc0/nvc0_state.c
index b6666ca..dca06f4 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_state.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_state.c
@@ -1089,9 +1089,11 @@ nvc0_set_transform_feedback_targets(struct pipe_context
*pipe,
       pipe_so_target_reference(&nvc0->tfbbuf[i], targets[i]);
    }
    for (; i < nvc0->num_tfbbufs; ++i) {
-      nvc0->tfbbuf_dirty |= 1 << i;
-      nvc0_so_target_save_offset(pipe, nvc0->tfbbuf[i], i, &serialize);
-      pipe_so_target_reference(&nvc0->tfbbuf[i], NULL);
+      if (nvc0->tfbbuf[i]) {
+         nvc0->tfbbuf_dirty |= 1 << i;
+         nvc0_so_target_save_offset(pipe, nvc0->tfbbuf[i], i,
&serialize);
+         pipe_so_target_reference(&nvc0->tfbbuf[i], NULL);
+      }
    }
    nvc0->num_tfbbufs = num_targets;
 
-- 
2.0.5

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

Marek

On Sat, Feb 14, 2015 at 7:46 AM, Ilia Mirkin <imirkin at alum.mit.edu>
wrote:
> If a transform feedback buffer's size is 0, st_bufferobj_data
doesn't
> end up creating a buffer for it. There's no point in trying to write to
> such a buffer, so just pretend as if it's not really there.
>
> This fixes arb_gpu_shader5-xfb-streams-without-invocations on nvc0.
>
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>  src/mesa/state_tracker/st_cb_xformfb.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/mesa/state_tracker/st_cb_xformfb.c
b/src/mesa/state_tracker/st_cb_xformfb.c
> index 8f75eda..a2bd86a 100644
> --- a/src/mesa/state_tracker/st_cb_xformfb.c
> +++ b/src/mesa/state_tracker/st_cb_xformfb.c
> @@ -122,7 +122,7 @@ st_begin_transform_feedback(struct gl_context *ctx,
GLenum mode,
>     for (i = 0; i < max_num_targets; i++) {
>        struct st_buffer_object *bo =
st_buffer_object(sobj->base.Buffers[i]);
>
> -      if (bo) {
> +      if (bo && bo->buffer) {
>           /* Check whether we need to recreate the target. */
>           if (!sobj->targets[i] ||
>               sobj->targets[i] == sobj->draw_count ||
> --
> 2.0.5
>
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