2 files changed, 18 insertions, 10 deletions

diff --git a/src/gallium/drivers/nouveau/nv50/nv50_surface.c b/src/gallium/drivers/nouveau/nv50/nv50_surface.c
index c64be0a348f..7a2402d72ed 100644
--- a/src/gallium/drivers/nouveau/nv50/nv50_surface.c
+++ b/src/gallium/drivers/nouveau/nv50/nv50_surface.c
@@ -1356,7 +1356,6 @@ nv50_blit_3d(struct nv50_context *nv50, const struct pipe_blit_info *info)
    float x0, x1, y0, y1, z;
    float dz;
    float x_range, y_range;
-   float tri_x, tri_y;
 
    blit->mode = nv50_blit_select_mode(info);
    blit->color_mask = nv50_blit_derive_color_mask(info);
@@ -1377,14 +1376,11 @@ nv50_blit_3d(struct nv50_context *nv50, const struct pipe_blit_info *info)
    x_range = (float)info->src.box.width / (float)info->dst.box.width;
    y_range = (float)info->src.box.height / (float)info->dst.box.height;
 
-   tri_x = 16384 << nv50_miptree(dst)->ms_x;
-   tri_y = 16384 << nv50_miptree(dst)->ms_y;
-
    x0 = (float)info->src.box.x - x_range * (float)info->dst.box.x;
    y0 = (float)info->src.box.y - y_range * (float)info->dst.box.y;
 
-   x1 = x0 + tri_x * x_range;
-   y1 = y0 + tri_y * y_range;
+   x1 = x0 + 16384.0f * x_range;
+   y1 = y0 + 16384.0f * y_range;
 
    x0 *= (float)(1 << nv50_miptree(src)->ms_x);
    x1 *= (float)(1 << nv50_miptree(src)->ms_x);
@@ -1457,7 +1453,7 @@ nv50_blit_3d(struct nv50_context *nv50, const struct pipe_blit_info *info)
       PUSH_DATAf(push, y0);
       PUSH_DATAf(push, z);
       BEGIN_NV04(push, NV50_3D(VTX_ATTR_2F_X(0)), 2);
-      PUSH_DATAf(push, tri_x);
+      PUSH_DATAf(push, 16384.0f);
       PUSH_DATAf(push, 0.0f);
       BEGIN_NV04(push, NV50_3D(VTX_ATTR_3F_X(1)), 3);
       PUSH_DATAf(push, x0);
@@ -1465,7 +1461,7 @@ nv50_blit_3d(struct nv50_context *nv50, const struct pipe_blit_info *info)
       PUSH_DATAf(push, z);
       BEGIN_NV04(push, NV50_3D(VTX_ATTR_2F_X(0)), 2);
       PUSH_DATAf(push, 0.0f);
-      PUSH_DATAf(push, tri_y);
+      PUSH_DATAf(push, 16384.0f);
       BEGIN_NV04(push, NV50_3D(VERTEX_END_GL), 1);
       PUSH_DATA (push, 0);
    }
diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
index 5f630149836..2b38fe6e7f5 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
@@ -1276,6 +1276,18 @@ nvc0_blit_3d(struct nvc0_context *nvc0, const struct pipe_blit_info *info)
     * render target, with scissors defining the destination region.
     * The vertex is supplied with non-normalized texture coordinates
     * arranged in a way to yield the desired offset and scale.
+    *
+    * Note that while the source texture is presented to the sampler as
+    * non-MSAA (even if it is), the destination texture is treated as MSAA for
+    * rendering. This means that
+    *  - destination coordinates shouldn't be scaled
+    *  - without per-sample rendering, the target will be a solid-fill for all
+    *    of the samples
+    *
+    * The last point implies that this process is very bad for 1:1 blits, as
+    * well as scaled blits between MSAA surfaces. This works fine for
+    * upscaling and downscaling though. The 1:1 blits should ideally be
+    * handled by the 2d engine, which can do it perfectly.
     */
 
    minx = info->dst.box.x;
@@ -1364,14 +1376,14 @@ nvc0_blit_3d(struct nvc0_context *nvc0, const struct pipe_blit_info *info)
       *(vbuf++) = fui(y0);
       *(vbuf++) = fui(z);
 
-      *(vbuf++) = fui(32768 << nv50_miptree(dst)->ms_x);
+      *(vbuf++) = fui(32768.0f);
       *(vbuf++) = fui(0.0f);
       *(vbuf++) = fui(x1);
       *(vbuf++) = fui(y0);
       *(vbuf++) = fui(z);
 
       *(vbuf++) = fui(0.0f);
-      *(vbuf++) = fui(32768 << nv50_miptree(dst)->ms_y);
+      *(vbuf++) = fui(32768.0f);
       *(vbuf++) = fui(x0);
       *(vbuf++) = fui(y1);
       *(vbuf++) = fui(z);