From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Panella Subject: Re: [Xen-devel] [PATCH 1/1] XEN: Use correct masking in xen_swiotlb_alloc_coherent. Date: Tue, 4 Sep 2012 16:12:25 +0100 Message-ID: <50461A59.2050504@citrix.com> References: <1346407072-6405-1-git-send-email-stefano.panella@citrix.com> <5040B249.4000306@citrix.com> <20120831164010.GA18929@localhost.localdomain> <50460B2E.3020200@citrix.com> <20120904143731.GC23361@phenom.dumpdata.com> <50461654.5040901@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50461654.5040901@citrix.com> Sender: linux-kernel-owner@vger.kernel.org To: David Vrabel Cc: Konrad Rzeszutek Wilk , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 09/04/2012 03:55 PM, David Vrabel wrote: > On 04/09/12 15:37, Konrad Rzeszutek Wilk wrote: >> On Tue, Sep 04, 2012 at 03:07:42PM +0100, Stefano Panella wrote: >>> So if hwdev->coherent_dma_mask is set to 0xffffffffffffffff our dma_mask will >>> be u64 set to 0xffffffffffffffff even if we set it to DMA_BIT_MASK(32) previously. >> That is what I was missing. Let me include that in the git commit and also >> put this patch on the stable tree. > Note that this appears to be a work around for a bug in the sound system > or Intel HDA device driver which is incorrectly truncating a dma_addr_t > to a u32. So by ensuring a DMA_BIT_MASK(32) when the dma_addr_t is > truncated it still works. > > David Sorry David, I am not completely sure I understand your argument in favour of a bug in the sound system or Intel HDA device driver. Could you please elaborate more in detail about this? Thanks, Stefano