[Mesa-dev] [PATCH 2/2] NEEDS TEST nvc0: always keep TSC slot 0 bound to fix TXF

[Ilia Mirkin]

Same as on nv50, the TXF op always uses the TSC bound to slot 0,
returning blank values if nothing is bound.

An earlier change arranges for the TSC entries list to always have valid
data at entry 0, so here we just make use of it.

Fixes arb_texture_buffer_object-subdata-sync among others.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

I haven't tested this on nvc0 hardware yet, but it seems like it should
work, based on my original investigation and the results on nv50.
However all this stuff is subtle, so even if it looks like it works in
principle, it might be missing some bit in practice. Sending it out now
though.

 src/gallium/drivers/nouveau/nvc0/nvc0_context.c |  8 ++++++++
 src/gallium/drivers/nouveau/nvc0/nvc0_tex.c     | 12 ++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_context.c b/src/gallium/drivers/nouveau/nvc0/nvc0_context.c
index 2d46a90ddb4..08ca0a204d3 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_context.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_context.c
@@ -488,6 +488,14 @@ nvc0_create(struct pipe_screen *pscreen, void *priv, unsigned ctxflags)
    if (!screen->tsc.entries[0])
       nvc0_upload_tsc0(nvc0);
 
+   // On Fermi, mark samplers dirty so that the proper binding can happen
+   if (screen->base.class_3d < NVE4_3D_CLASS) {
+      for (int s = 0; s < 6; s++)
+         nvc0->samplers_dirty[s] = 1;
+      nvc0->dirty_3d |= NVC0_NEW_3D_SAMPLERS;
+      nvc0->dirty_cp |= NVC0_NEW_CP_SAMPLERS;
+   }
+
    return pipe;
 
 out_err:
diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_tex.c b/src/gallium/drivers/nouveau/nvc0/nvc0_tex.c
index b7e3df1a8ae..7d6c2febfdb 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_tex.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_tex.c
@@ -657,6 +657,18 @@ nvc0_validate_tsc(struct nvc0_context *nvc0, int s)
 
    nvc0->state.num_samplers[s] = nvc0->num_samplers[s];
 
+   // TXF, in unlinked tsc mode, will always use sampler 0. So we have to
+   // ensure that it remains bound. Its contents don't matter, all samplers we
+   // ever create have the SRGB_CONVERSION bit set, so as long as the first
+   // entry is initialized, we're good to go. This is the only bit that has
+   // any effect on what TXF does.
+   if ((nvc0->samplers_dirty[s] & 1) && !nvc0->samplers[s][0]) {
+      assert(n > 0);
+      // We're guaranteed that the first command refers to the first slot, so
+      // we're not overwriting a valid entry.
+      commands[0] = (0 << 12) | (0 << 4) | 1;
+   }
+
    if (n) {
       if (unlikely(s == 5))
          BEGIN_NIC0(push, NVC0_CP(BIND_TSC), n);
-- 
2.18.1