From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [Xen-devel] [PATCH 1/1] XEN: Use correct masking in xen_swiotlb_alloc_coherent. Date: Tue, 4 Sep 2012 15:55:16 +0100 Message-ID: <50461654.5040901@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> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120904143731.GC23361@phenom.dumpdata.com> Sender: linux-kernel-owner@vger.kernel.org To: Konrad Rzeszutek Wilk Cc: Stefano Panella , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org 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