v3d: rebind sampler view if resource changed the BO

When discarding the whole resource to create a new one, if this resource
is used by a sampler view, a rebind must be done to use the new
resource.

But this must be done when setting the sampler views, because we don't
have access to those samplers before.

v2:
 - Pack shader state on setting sampler views (Iago)
 - Use a serial ID to know when to rebind sampler views (Juan)

v3:
 - Move check to caller (Iago)
 - Keep rebind sampler view on BO change (Iago)

v4:
 - Rename "serial_bo" to "serial_id" (Iago)
 - Add comments (Iago)

Fixes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/6027
Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15171>

src/gallium/drivers/v3d/v3d_context.h

@@ -165,6 +165,12 @@ struct v3d_sampler_view {
          * raster texture.
          */
         struct pipe_resource *texture;
+
+        /* A serial ID used to identify cases where a new BO has been created
+         * and we need to rebind a sampler view that was created against the
+         * previous BO to to point to the new one.
+         */
+        uint32_t serial_id;
 };
 
 struct v3d_sampler_state {

src/gallium/drivers/v3d/v3d_resource.c

@@ -103,6 +103,7 @@ v3d_resource_bo_alloc(struct v3d_resource *rsc)
         if (bo) {
                 v3d_bo_unreference(&rsc->bo);
                 rsc->bo = bo;
+                rsc->serial_id++;
                 v3d_debug_resource_layout(rsc, "alloc");
                 return true;
         } else {
@@ -186,6 +187,13 @@ v3d_map_usage_prep(struct pipe_context *pctx,
                                 v3d->dirty |= V3D_DIRTY_VTXBUF;
                         if (prsc->bind & PIPE_BIND_CONSTANT_BUFFER)
                                 v3d->dirty |= V3D_DIRTY_CONSTBUF;
+                        /* Since we are changing the texture BO we need to
+                         * update any bound samplers to point to the new
+                         * BO. Notice we can have samplers that are not
+                         * currently bound to the state that won't be
+                         * updated. These will be fixed when they are bound in
+                         * v3d_set_sampler_views.
+                         */
                         if (prsc->bind & PIPE_BIND_SAMPLER_VIEW)
                                 rebind_sampler_views(v3d, rsc);
                 } else {
@@ -740,6 +748,8 @@ v3d_resource_setup(struct pipe_screen *pscreen,
                 }
         }
 
+        rsc->serial_id++;
+
         assert(rsc->cpp);
 
         return rsc;

src/gallium/drivers/v3d/v3d_resource.h

@@ -119,6 +119,14 @@ struct v3d_resource {
          */
         uint32_t initialized_buffers;
 
+        /**
+         * A serial ID that is incremented every time a new BO is bound to a
+         * resource. We use this to track scenarios where we might need to
+         * update other resources to point to the new BO (like sampler states
+         * when a texture BO changes).
+         */
+        uint32_t serial_id;
+
         enum pipe_format internal_format;
 
         /* Resource storing the S8 part of a Z32F_S8 resource, or NULL. */

src/gallium/drivers/v3d/v3dx_state.c

@@ -923,11 +923,14 @@ v3dX(create_texture_shader_state_bo)(struct v3d_context *v3d,
                                      struct v3d_sampler_view *so)
 {
         struct pipe_resource *prsc = so->texture;
+        struct v3d_resource *rsc = v3d_resource(prsc);
         const struct pipe_sampler_view *cso = &so->base;
         struct v3d_screen *screen = v3d->screen;
 
         void *map;
 
+        assert(so->serial_id != rsc->serial_id);
+
 #if V3D_VERSION >= 40
         v3d_bo_unreference(&so->bo);
         so->bo = v3d_bo_alloc(v3d->screen,
@@ -1010,6 +1013,8 @@ v3dX(create_texture_shader_state_bo)(struct v3d_context *v3d,
                                                               cso->format);
                 }
         };
+
+        so->serial_id = rsc->serial_id;
 }
 
 static struct pipe_sampler_view *
@@ -1205,6 +1210,18 @@ v3d_set_sampler_views(struct pipe_context *pctx,
                 } else {
                         pipe_sampler_view_reference(&stage_tex->textures[i], views[i]);
                 }
+                /* If our sampler serial doesn't match our texture serial it
+                 * means the texture has been updated with a new BO, in which
+                 * case we need to update the sampler state to point to the
+                 * new BO as well
+                 */
+                if (stage_tex->textures[i]) {
+                        struct v3d_sampler_view *so =
+                                v3d_sampler_view(stage_tex->textures[i]);
+                        struct v3d_resource *rsc = v3d_resource(so->texture);
+                        if (so->serial_id != rsc->serial_id)
+                                v3d_create_texture_shader_state_bo(v3d, so);
+                }
         }
 
         for (; i < stage_tex->num_textures; i++) {