For some reason, streaming copies to write-combined regions are

extremely sensitive to the characteristics of how the source data is
retrieved.  By reordering the source reads in the rgba to bgra
conversion, the speed of this operation increases by half.

src/mesa/main/texstore.c

@@ -1222,6 +1222,43 @@ _mesa_texstore_argb8888(STORE_PARAMS)
          dstImage += dstImageStride;
       }
    }
+   else if (!ctx->_ImageTransferState &&
+            !srcPacking->SwapBytes &&
+	    dstFormat == &_mesa_texformat_argb8888 &&
+            srcFormat == GL_RGBA &&
+            (srcType == GL_UNSIGNED_BYTE && littleEndian)) {
+
+      int img, row, col;
+      GLubyte *dstImage = (GLubyte *) dstAddr
+                        + dstZoffset * dstImageStride
+                        + dstYoffset * dstRowStride
+                        + dstXoffset * dstFormat->TexelBytes;
+
+      /* For some reason, streaming copies to write-combined regions
+       * are extremely sensitive to the characteristics of how the
+       * source data is retrieved.  By reordering the source reads to
+       * be in-order, the speed of this operation increases by half.
+       * Strangely the same isn't required for the RGB path, above.
+       */
+      for (img = 0; img < srcDepth; img++) {
+         const GLint srcRowStride = _mesa_image_row_stride(srcPacking,
+                                                 srcWidth, srcFormat, srcType);
+         GLubyte *srcRow = (GLubyte *) _mesa_image_address(dims, srcPacking,
+                  srcAddr, srcWidth, srcHeight, srcFormat, srcType, img, 0, 0);
+         GLubyte *dstRow = dstImage;
+         for (row = 0; row < srcHeight; row++) {
+            for (col = 0; col < srcWidth; col++) {
+               *(GLuint *)(dstRow + col * 4)  = (srcRow[col * 4 + RCOMP] << 16 |
+						 srcRow[col * 4 + GCOMP] << 8 |
+						 srcRow[col * 4 + BCOMP] << 0 |
+						 srcRow[col * 4 + ACOMP] << 24);
+            }
+            dstRow += dstRowStride;
+            srcRow += srcRowStride;
+         }
+         dstImage += dstImageStride;
+      }
+   }
    else if (!ctx->_ImageTransferState &&
             !srcPacking->SwapBytes &&
 	    dstFormat == &_mesa_texformat_argb8888 &&