From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751290Ab1IVAXy (ORCPT ); Wed, 21 Sep 2011 20:23:54 -0400 Received: from sestofw01.enea.se ([192.36.1.252]:3145 "HELO mx-3.enea.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1750874Ab1IVAXx (ORCPT ); Wed, 21 Sep 2011 20:23:53 -0400 X-Greylist: delayed 322 seconds by postgrey-1.27 at vger.kernel.org; Wed, 21 Sep 2011 20:23:53 EDT Message-ID: <4E7A7ED4.7080805@enea.com> Date: Thu, 22 Sep 2011 02:18:28 +0200 From: Arvid Brodin User-Agent: Thunderbird 2.0.0.24 (X11/20100411) MIME-Version: 1.0 To: Subject: dma_unmap_single() lacking cache sync on some archs? Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [172.23.1.38] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I would expect cache synchronization for DMA_TO_DEVICE and DMA_BIDIRECTIONAL when dma_map_single() is called, and for DMA_FROM_DEVICE and DMA_BIDIRECTIONAL when dma_unmap_single() is called. However, on some architechtures (at least avr32, blackfin, ...), cache synchronization only happens when dma_map_single() is called (and then irrespective of DMA direction). dma_unmap_single() is a no-op for these archs. Isn't this a bug? (Please CC me in responses.) -- Arvid Brodin Enea Services Stockholm AB