diff --git a/src/mesa/swrast/s_readpix.c b/src/mesa/swrast/s_readpix.c
index 9fe0752a37f..c4fe27b7eda 100644
--- a/src/mesa/swrast/s_readpix.c
+++ b/src/mesa/swrast/s_readpix.c
@@ -191,7 +191,10 @@ fast_read_rgba_pixels( struct gl_context *ctx,
    if (!rb)
       return GL_FALSE;
 
-   ASSERT(rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB ||
+   ASSERT(rb->_BaseFormat == GL_RGBA ||
+	  rb->_BaseFormat == GL_RGB ||
+	  rb->_BaseFormat == GL_RG ||
+	  rb->_BaseFormat == GL_RED ||
 	  rb->_BaseFormat == GL_ALPHA);
 
    /* clipping should have already been done */
diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c
index 3240b135774..34525d4407a 100644
--- a/src/mesa/swrast/s_span.c
+++ b/src/mesa/swrast/s_span.c
@@ -1347,7 +1347,10 @@ _swrast_read_rgba_span( struct gl_context *ctx, struct gl_renderbuffer *rb,
 
       ASSERT(rb);
       ASSERT(rb->GetRow);
-      ASSERT(rb->_BaseFormat == GL_RGB || rb->_BaseFormat == GL_RGBA ||
+      ASSERT(rb->_BaseFormat == GL_RGBA ||
+	     rb->_BaseFormat == GL_RGB ||
+	     rb->_BaseFormat == GL_RG ||
+	     rb->_BaseFormat == GL_RED ||
 	     rb->_BaseFormat == GL_ALPHA);
 
       if (rb->DataType == dstType) {