st/mesa: fix the layer of VDPAU surface samplers

A (latent) bug in VDPAU interop was exposed by commit
e5cc84dd43be066c1dd418e32f5ad258e31a150a.

Before that commit, the st_vdpau code created samplers with
first_layer == last_layer == 1 that the general texture handling code
would immediately delete and re-create, because the layer does not match
the information in the GL texture object.

This was correct behavior at least in the DMABUF case, because the imported
resource is supposed to have the correct offset already applied.  In the
non-DMABUF case, this was just plain wrong but apparently nobody noticed.

After that commit, the state tracker assumes that an existing sampler is
correct at all times.  Existing samplers are supposed to be deleted when
they may become invalid, and they will be created on-demand.  This meant
that the sampler with first_layer == last_layer == 1 stuck around, leading
to rendering artefacts (on radeonsi), command stream failures (on r600), and
assertions (in debug builds everywhere).

This patch fixes the problem by simply not creating a sampler at all in
st_vdpau_map_surface.  We rely on the generic texture code to do the right
thing, adding the layer_override to make the non-DMABUF case work.

v2: add the layer_override

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98512
Cc: 13.0 <mesa-stable@lists.freedesktop.org>
Cc: Christian König <deathsimple@vodafone.de>
Cc: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
Reviewed-by: Christian König <christian.koenig@amd.com>
(cherry picked from commit 322483f71b068b3bbf69e5434e888f3fd3f4589e)

3 files changed, 27 insertions, 17 deletions

diff --git a/src/mesa/state_tracker/st_sampler_view.c b/src/mesa/state_tracker/st_sampler_view.c
index 9fe0bfe..2b2fa8b 100644
--- a/src/mesa/state_tracker/st_sampler_view.c
+++ b/src/mesa/state_tracker/st_sampler_view.c
@@ -430,8 +430,12 @@ st_create_texture_sampler_view_from_stobj(struct st_context *st,
       templ.u.tex.first_level = stObj->base.MinLevel + stObj->base.BaseLevel;
       templ.u.tex.last_level = last_level(stObj);
       assert(templ.u.tex.first_level <= templ.u.tex.last_level);
-      templ.u.tex.first_layer = stObj->base.MinLayer;
-      templ.u.tex.last_layer = last_layer(stObj);
+      if (stObj->layer_override) {
+         templ.u.tex.first_layer = templ.u.tex.last_layer = stObj->layer_override;
+      } else {
+         templ.u.tex.first_layer = stObj->base.MinLayer;
+         templ.u.tex.last_layer = last_layer(stObj);
+      }
       assert(templ.u.tex.first_layer <= templ.u.tex.last_layer);
       templ.target = gl_target_to_pipe(stObj->base.Target);
    }
@@ -478,8 +482,11 @@ st_get_texture_sampler_view_from_stobj(struct st_context *st,
          assert(stObj->base.MinLevel + stObj->base.BaseLevel ==
                 view->u.tex.first_level);
          assert(last_level(stObj) == view->u.tex.last_level);
-         assert(stObj->base.MinLayer == view->u.tex.first_layer);
-         assert(last_layer(stObj) == view->u.tex.last_layer);
+         assert(stObj->layer_override || stObj->base.MinLayer == view->u.tex.first_layer);
+         assert(stObj->layer_override || last_layer(stObj) == view->u.tex.last_layer);
+         assert(!stObj->layer_override ||
+                (stObj->layer_override == view->u.tex.first_layer &&
+                 stObj->layer_override == view->u.tex.last_layer));
       }
    }
    else {
diff --git a/src/mesa/state_tracker/st_texture.h b/src/mesa/state_tracker/st_texture.h
index 730843a..0ce7989 100644
--- a/src/mesa/state_tracker/st_texture.h
+++ b/src/mesa/state_tracker/st_texture.h
@@ -108,6 +108,15 @@ struct st_texture_object
     */
    enum pipe_format surface_format;
 
+   /* When non-zero, samplers should use this layer instead of the one
+    * specified by the GL state.
+    *
+    * This is used for VDPAU interop, where imported pipe_resources may be
+    * array textures (containing layers with different fields) even though the
+    * GL state describes one non-array texture per field.
+    */
+   uint layer_override;
+
    /** The glsl version of the shader seen during the previous validation */
    unsigned prev_glsl_version;
    /** The value of the sampler's sRGBDecode state at the previous validation */
diff --git a/src/mesa/state_tracker/st_vdpau.c b/src/mesa/state_tracker/st_vdpau.c
index 7912057..0273815 100644
--- a/src/mesa/state_tracker/st_vdpau.c
+++ b/src/mesa/state_tracker/st_vdpau.c
@@ -189,8 +189,8 @@ st_vdpau_map_surface(struct gl_context *ctx, GLenum target, GLenum access,
    struct st_texture_image *stImage = st_texture_image(texImage);
 
    struct pipe_resource *res;
-   struct pipe_sampler_view templ, **sampler_view;
    mesa_format texFormat;
+   uint layer_override = 0;
 
    if (output) {
       res = st_vdpau_output_surface_dma_buf(ctx, vdpSurface);
@@ -201,8 +201,10 @@ st_vdpau_map_surface(struct gl_context *ctx, GLenum target, GLenum access,
    } else {
       res = st_vdpau_video_surface_dma_buf(ctx, vdpSurface, index);
 
-      if (!res)
+      if (!res) {
          res = st_vdpau_video_surface_gallium(ctx, vdpSurface, index);
+         layer_override = index & 1;
+      }
    }
 
    if (!res) {
@@ -233,18 +235,8 @@ st_vdpau_map_surface(struct gl_context *ctx, GLenum target, GLenum access,
    st_texture_release_all_sampler_views(st, stObj);
    pipe_resource_reference(&stImage->pt, res);
 
-   u_sampler_view_default_template(&templ, res, res->format);
-   templ.u.tex.first_layer = index & 1;
-   templ.u.tex.last_layer = index & 1;
-   templ.swizzle_r = GET_SWZ(stObj->base._Swizzle, 0);
-   templ.swizzle_g = GET_SWZ(stObj->base._Swizzle, 1);
-   templ.swizzle_b = GET_SWZ(stObj->base._Swizzle, 2);
-   templ.swizzle_a = GET_SWZ(stObj->base._Swizzle, 3);
-
-   sampler_view = st_texture_get_sampler_view(st, stObj);
-   *sampler_view = st->pipe->create_sampler_view(st->pipe, res, &templ);
-
    stObj->surface_format = res->format;
+   stObj->layer_override = layer_override;
 
    _mesa_dirty_texobj(ctx, texObj);
    pipe_resource_reference(&res, NULL);
@@ -264,6 +256,8 @@ st_vdpau_unmap_surface(struct gl_context *ctx, GLenum target, GLenum access,
    st_texture_release_all_sampler_views(st, stObj);
    pipe_resource_reference(&stImage->pt, NULL);
 
+   stObj->layer_override = 0;
+
    _mesa_dirty_texobj(ctx, texObj);
 
    st_flush(st, NULL, 0);