3 files changed, 10 insertions, 6 deletions
diff --git a/src/mesa/main/formats.c b/src/mesa/main/formats.c
index 834d4c81ffb..f35239527b5 100644
--- a/src/mesa/main/formats.c
+++ b/src/mesa/main/formats.c
@@ -2516,14 +2516,16 @@ _mesa_format_to_type_and_comps(gl_format format,
 /**
  * Check if a gl_format exactly matches a GL formaat/type combination
  * such that we can use memcpy() from one to the other.
- *
- * Note: this matching assumes that GL_PACK/UNPACK_SWAP_BYTES is unset.
- *
+ * \param gl_format  a MESA_FORMAT_x value
+ * \param format  the user-specified image format
+ * \param type  the user-specified image datatype
+ * \param swapBytes  typically the current pixel pack/unpack byteswap state
  * \return GL_TRUE if the formats match, GL_FALSE otherwise.
  */
 GLboolean
 _mesa_format_matches_format_and_type(gl_format gl_format,
-				     GLenum format, GLenum type)
+				     GLenum format, GLenum type,
+                                     GLboolean swapBytes)
 {
    const GLboolean littleEndian = _mesa_little_endian();
 
diff --git a/src/mesa/main/formats.h b/src/mesa/main/formats.h
index 9609343387f..3a694a813de 100644
--- a/src/mesa/main/formats.h
+++ b/src/mesa/main/formats.h
@@ -343,7 +343,8 @@ _mesa_format_num_components(gl_format format);
 
 GLboolean
 _mesa_format_matches_format_and_type(gl_format gl_format,
-				     GLenum format, GLenum type);
+				     GLenum format, GLenum type,
+                                     GLboolean swapBytes);
 
 
 #ifdef __cplusplus
diff --git a/src/mesa/main/readpix.c b/src/mesa/main/readpix.c
index 84b5224c858..71de0b31298 100644
--- a/src/mesa/main/readpix.c
+++ b/src/mesa/main/readpix.c
@@ -209,7 +209,8 @@ fast_read_rgba_pixels_memcpy( struct gl_context *ctx,
    GLubyte *dst, *map;
    int dstStride, stride, j, texelBytes;
 
-   if (!_mesa_format_matches_format_and_type(rb->Format, format, type))
+   if (!_mesa_format_matches_format_and_type(rb->Format, format, type,
+                                             ctx->Pack.SwapBytes))
       return GL_FALSE;
 
    /* check for things we can't handle here */