Return-path: Received: from mail-gw1-out.broadcom.com ([216.31.210.62]:7282 "EHLO mail-gw1-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756529AbaLILHb (ORCPT ); Tue, 9 Dec 2014 06:07:31 -0500 Message-ID: <5486D7EF.6010902@broadcom.com> (sfid-20141209_120748_308363_C58AA39B) Date: Tue, 9 Dec 2014 12:07:27 +0100 From: Arend van Spriel MIME-Version: 1.0 To: Russell King - ARM Linux CC: Catalin Marinas , Arnd Bergmann , "linux-arm-kernel@lists.infradead.org" , brcm80211-dev-list , linux-wireless , "linux-kernel@vger.kernel.org" , Will Deacon , "Hante Meuleman" , "hauke@hauke-m.de" , David Miller , Marek Szyprowski Subject: Re: using DMA-API on ARM References: <5481794E.4050406@broadcom.com> <2863746.4sUSEYqahB@wuerfel> <20141208160316.GM16185@e104818-lin.cambridge.arm.com> <5485D97D.1040404@broadcom.com> <5486CCBC.3@broadcom.com> <20141209102904.GJ11285@n2100.arm.linux.org.uk> In-Reply-To: <20141209102904.GJ11285@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/09/14 11:29, Russell King - ARM Linux wrote: > On Tue, Dec 09, 2014 at 11:19:40AM +0100, Arend van Spriel wrote: >> The issue did not trigger overnight so it seems setting bit 22> Attribute _Override_ Enable> solves the issue over here. Now the question is >> how to move forward with this. As I understood from Catalin this patch was >> not included as it was not considered responsibility of the linux kernel. > > It is preferable for firmware to configure the L2 cache appropriately, > which includes things like the prefetch offsets as well as feature bits > like bit 22. > > I think what I'll do is queue up a patch which adds a warning if bit 22 > is not set, suggesting that firmware is updated to set this bit. I was thinking in the same direction. Thanks to you all for looking into this. It did not feel right to use the dma_sync_single_for_cpu() for memory allocated with dma_alloc_coherent() and I am glad this got cleared up. Regards, Arend