diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index fef538a8c14..2d242135a42 100644
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -4290,6 +4290,25 @@ frame_buffer_texture(GLuint framebuffer, GLenum target,
       }
 
       if (!no_error) {
+         /* EXT_multisampled_render_to_texture:
+
+            If samples is greater than the 
+            value of MAX_SAMPLES_EXT, then the error INVALID_VALUE is generated. 
+            An INVALID_OPERATION error is generated if samples is greater than
+            the maximum number of samples supported for target and its
+            internalformat. If samples is zero, then TEXTURE_SAMPLES_EXT is set
+            to zero, and FramebufferTexture2DMultisampleEXT behaves like
+            FramebufferTexture2D.
+          */
+         if (samples > ctx->Const.MaxSamples) {
+            _mesa_error(ctx, GL_INVALID_VALUE, "%s(invalid sample count %u)",
+                        func, samples);
+         }
+         if (samples > ctx->Const.MaxFramebufferSamples) {
+            _mesa_error(ctx, GL_INVALID_OPERATION, "%s(invalid sample count %u)",
+                        func, samples);
+         }
+
          if (!check_layered) {
             if (!check_texture_target(ctx, texObj->Target, func))
                return;
diff --git a/src/mesa/main/renderbuffer.c b/src/mesa/main/renderbuffer.c
index af15081fe1c..3b11c5c3e07 100644
--- a/src/mesa/main/renderbuffer.c
+++ b/src/mesa/main/renderbuffer.c
@@ -630,6 +630,27 @@ _mesa_update_renderbuffer_surface(struct gl_context *ctx,
                            last_layer);
    }
 
+   int nr_samples = rb->rtt_nr_samples;
+   if (rb->rtt_nr_samples && rb->rtt_nr_samples != resource->nr_samples) {
+      assert(!resource->nr_samples);
+      /* EXT_multisampled_render_to_texture:
+
+         Otherwise samples represents a request for a desired minimum number 
+         of samples. Since different implementations may support different 
+         sample counts for multisampled rendering, the actual number of samples 
+         allocated for the image is implementation-dependent. However, the 
+         resulting value for TEXTURE_SAMPLES_EXT is guaranteed to be greater 
+         than or equal to samples and no more than the next larger sample count 
+         supported by the implementation.
+       */
+      for (unsigned i = rb->rtt_nr_samples + 1; i <= ctx->Const.MaxFramebufferSamples; i++) {
+         if (!ctx->st->screen->is_format_supported(ctx->st->screen, format, resource->target, i, i, resource->bind))
+            continue;
+         nr_samples = i;
+         break;
+      }
+   }
+
    struct pipe_surface **psurf =
       enable_srgb ? &rb->surface_srgb : &rb->surface_linear;
    struct pipe_surface *surf = *psurf;
@@ -641,7 +662,7 @@ _mesa_update_renderbuffer_surface(struct gl_context *ctx,
        surf->texture != resource ||
        surf->width != rtt_width ||
        surf->height != rtt_height ||
-       surf->nr_samples != rb->rtt_nr_samples ||
+       surf->nr_samples != nr_samples ||
        surf->u.tex.level != level ||
        surf->u.tex.first_layer != first_layer ||
        surf->u.tex.last_layer != last_layer) {
@@ -649,7 +670,7 @@ _mesa_update_renderbuffer_surface(struct gl_context *ctx,
       struct pipe_surface surf_tmpl;
       memset(&surf_tmpl, 0, sizeof(surf_tmpl));
       surf_tmpl.format = format;
-      surf_tmpl.nr_samples = rb->rtt_nr_samples;
+      surf_tmpl.nr_samples = nr_samples;
       surf_tmpl.u.tex.level = level;
       surf_tmpl.u.tex.first_layer = first_layer;
       surf_tmpl.u.tex.last_layer = last_layer;