From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: Why is AHA152X_CS !64BIT? Date: Tue, 07 Sep 2010 17:10:08 -0500 Message-ID: <1283897409.22844.7.camel@mulgrave.site> References: <4C72D310.4040004@suse.cz> <4C7B924D.6030703@panasas.com> <201009071712.54867.konrad@darnok.org> <4C86B1A4.8030308@oracle.com> <4C86B320.8090709@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from cantor2.suse.de ([195.135.220.15]:51005 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752750Ab0IGWKQ (ORCPT ); Tue, 7 Sep 2010 18:10:16 -0400 In-Reply-To: <4C86B320.8090709@oracle.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Randy Dunlap Cc: Konrad Rzeszutek Wilk , Boaz Harrosh , Jiri Slaby , fischer@linux-buechse.de, linux-scsi@vger.kernel.org On Tue, 2010-09-07 at 14:48 -0700, Randy Dunlap wrote: > On 09/07/10 14:41, Randy Dunlap wrote: > > On 09/07/10 14:12, Konrad Rzeszutek Wilk wrote: > >> On Monday 30 August 2010 07:13:17 Boaz Harrosh wrote: > >>> On 08/23/2010 10:59 PM, Jiri Slaby wrote: > >>>> Hi, > >>>> > >>>> I see that the aha152x driver for pcmcia is marked as unsupported on > >>>> 64bit. But I also see a patch [1] which removes the restriction based on > >>>> user's testing in bugzilla [2]. > >>>> > >>>> Is there a reason why it would have to be marked as !64BIT? I'm asking > >>>> because there is an opensuse user with this card who updated to 64-bit > >>>> distro and lost this driver thereafter. > >>>> > >>>> [1] http://kerneltrap.org/mailarchive/linux-scsi/2010/3/6/6832393 > >>>> [2] https://bugzilla.kernel.org/show_bug.cgi?id=14333 > >>>> > >>>> thanks, > >>> > >>> If memory serves correctly, it might be that you need more then 4 Gbyte > >>> of memory installed to exercise the bug, something about IO bouncing > >>> addresses > 4G. > >> > >> If the machine is using SWIOTLB, then the bounce buffer would be activated. By > >> default if your machine has more than 4GB compiled under x86_64 the SWIOTLB > >> is turned on - but if you have an Intel/AMD IOMMU it gets turned off. Which > >> is OK as the Intel/AMD IOMMUs would handle the 4GB restricted devices. So as > >> long as the driver has pci_dma_mask_set. > >> > >> Looking at the git gui blame tool history, the reason that was added was > >> for 'allow drivers to be built non-modular'. > > > > 023ae619 (Robert P. J. Day 2007-03-26 16:06:45 -0400 14) depends on !64BIT > > > > That commit just removed the "depends on m" part: > > > > - depends on m && !64BIT > > + depends on !64BIT > > > > > >> So, does this driver build if you make it non-modular? > > > > It shouldn't since it still depends on !64BIT. > > > > I expect someone thought or had evidence that the driver was not 64-bit clean. > > > > Is the bitkeeper kernel repo still visible somewhere? > > Looks like we would need to look at it for patch history that far back. > > > > http://linux.bkbits.net:8080/linux-2.6/?PAGE=cset&REV=3fe0bc41KO89ooP68UcrHEMVVAfDnw > > but it doesn't quite make sense to me. Sure, no ISA on x86_64, but that does not > mean no PCMCIA on x86_64. Actually, the patch is this one: http://permalink.gmane.org/gmane.linux.scsi/5835 The complaint is that the driver spews warnings on a 64 bit compile, so it's likely not 64 bit clean. James