Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754032AbYJJE4o (ORCPT ); Fri, 10 Oct 2008 00:56:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751675AbYJJE4f (ORCPT ); Fri, 10 Oct 2008 00:56:35 -0400 Received: from rv-out-0506.google.com ([209.85.198.229]:49266 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751011AbYJJE4e (ORCPT ); Fri, 10 Oct 2008 00:56:34 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references:x-google-sender-auth; b=eMTnQSVdO2dmURhuArAM5mDVEpk9w+K5W1C0YdDOASDfwzcrSAGLVweAZA8iWumFQH IzM78AayThEhZk2fsLgtDA2HzUBC7tkrTgXj+R5ue8e2MPdDzCfbKbxLq3zdrSbTDAI6 05supr4diQ3jdDF/nFp2kwcgTF3iPTOHmp1ZE= Message-ID: <86802c440810092156i18bb7699vb8e90d52accad781@mail.gmail.com> Date: Thu, 9 Oct 2008 21:56:33 -0700 From: "Yinghai Lu" To: "FUJITA Tomonori" Subject: Re: [PATCH] pci: print out DMA mask info Cc: grundler@parisc-linux.org, matthew@wil.cx, jbarnes@virtuousgeek.org, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org In-Reply-To: <20081010114003X.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <86802c440810091451y4a3caceg1abaa75464c40a72@mail.gmail.com> <20081009225533.GB1914@colo.lackof.org> <48EE8E55.4000009@kernel.org> <20081010114003X.fujita.tomonori@lab.ntt.co.jp> X-Google-Sender-Auth: 1e1ff014db6077d6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1880 Lines: 46 On Thu, Oct 9, 2008 at 7:40 PM, FUJITA Tomonori wrote: > On Thu, 09 Oct 2008 16:05:57 -0700 > Yinghai Lu wrote: > >> Grant Grundler wrote: >> > On Thu, Oct 09, 2008 at 02:51:32PM -0700, Yinghai Lu wrote: >> >> On Thu, Oct 9, 2008 at 2:35 PM, Matthew Wilcox wrote: >> >>> Why's that interesting to the sysadmin of the machine? To the driver >> >>> writer, certainly. But what's the use of it to the people using the >> >>> machine? >> > ... >> >> make linux kernel act like black box as other os? >> > >> > I don't understand your reply. >> > If someone thinks linux is a black box, printing this message won't help them. >> > >> could find out easily why some driver doesn't set dma mask correctly. >> like why >> qlogic qla2xxx only set consistent to 64bit, >> emulex lpfc not set consistent to 64bit > > IIRC, except for one SGI architecture, coherent_dma_mask is > meaningless, dma_mask is always equal to coherent_dma_mask. Lots of > IOMMU implementations ignore coherent_dma_mask and use dma_mask for > alloc_coherent(). Some drivers doesn't set up coherent_dma_mask. ehci_hcd 0000:00:02.1: using 31bit consistent DMA mask ==> ck804 ehci, is using 31bit for consistent dma mask, at still use 32 bit for dma mask. qlogic qla2xxx and emulex lpfc dma mask and consistent_dma_mask is different... could have some story for them at least gart iommu is honoring the consistent dma mask. by calling dma_alloc_coherent_mask(dev, flag) if device could use 64 bit coherent dma mask, that is driver problem... print it out could put them in focus. YH -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/