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From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Matthew Wilcox <matthew@wil.cx>, linux-scsi@vger.kernel.org
Subject: Re: [PATCH] [3/22] Remove unchecked_isa_dma in advansys.c
Date: Tue, 26 Feb 2008 07:18:18 -0800	[thread overview]
Message-ID: <1204039098.3254.63.camel@localhost.localdomain> (raw)
In-Reply-To: <20080226034402.GD21577@one.firstfloor.org>

On Tue, 2008-02-26 at 04:44 +0100, Andi Kleen wrote:
> On Mon, Feb 25, 2008 at 03:50:22PM -0700, Matthew Wilcox wrote:
> > On Mon, Feb 25, 2008 at 11:40:35PM +0100, Andi Kleen wrote:
> > > > (I must have fixed it somehow because it works on parisc, which is most
> > > > unforgiving of drivers which do DMA without the DMA API).
> > > 
> > > At least on x86 the DMA API cannot do ISA bouncing.
> > 
> > You're saying that if I set a 24-bit DMA mask, and then do a
> > pci_alloc_coherent(), x86 might hand me back something that's not
> > accessible?  That would be just broken.
> 
> No pci_alloc_coherent works, but pci_map_* will not.

Yes, it does ... dma_map is a flush/virt_to_phys on x86. so of course it
works.  If you mean it doesn't transform from > 24 bit phys to < 24 bit
phys, then yes; but that's not an API requirement; that's what bounce
buffering is all about, so for ISA devices we always only call dma_map
on < 24 bit phys addresses and it all works.

James



  reply	other threads:[~2008-02-26 15:18 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-24 23:35 [PATCH] [0/22] Remove isa_unchecked_dma and some more GFP_DMAs in the mid layer Andi Kleen
2008-02-24 23:35 ` [PATCH] [1/22] Add new sense_buffer_mask host template field Andi Kleen
2008-02-25 14:48   ` James Bottomley
2008-02-25 15:01     ` Andi Kleen
2008-02-24 23:35 ` [PATCH] [2/22] Remove unchecked_isa in BusLogic Andi Kleen
2008-02-24 23:35 ` [PATCH] [3/22] Remove unchecked_isa_dma in advansys.c Andi Kleen
2008-02-25 21:47   ` Matthew Wilcox
2008-02-25 22:40     ` Andi Kleen
2008-02-25 22:50       ` Matthew Wilcox
2008-02-25 22:54         ` Jeff Garzik
2008-02-25 22:58           ` James Bottomley
2008-02-26  3:44         ` Andi Kleen
2008-02-26 15:18           ` James Bottomley [this message]
2008-02-26 18:40             ` Matthew Wilcox
2008-02-26 13:56       ` Matthew Wilcox
2008-02-24 23:35 ` [PATCH] [4/22] Remove unchecked_isa_dma in gdth Andi Kleen
2008-02-24 23:35 ` [PATCH] [6/22] Remove unchecked_isa_dma in aha1542 Andi Kleen
2008-02-24 23:35 ` [PATCH] [7/22] Remove unchecked_isa_dma in aha152x/wd7000/sym53c416/u14-34f/NCR53c406a Andi Kleen
2008-02-24 23:35 ` [PATCH] [8/22] Remove random noop unchecked_isa_dma users Andi Kleen
2008-02-25 14:19   ` Salyzyn, Mark
2008-02-24 23:35 ` [PATCH] [10/22] Remove unchecked_isa_dma support for hostdata Andi Kleen
2008-02-24 23:35 ` [PATCH] [11/22] Remove unchecked_isa_dma checks in sg.c Andi Kleen
2008-02-24 23:35 ` [PATCH] [12/22] Remove GFP_DMAs/unchecked_isa_dma checks in scsi_scan.c Andi Kleen
2008-02-25 14:46   ` James Bottomley
2008-02-25 14:58     ` Andi Kleen
2008-02-25 15:04       ` James Bottomley
2008-02-25 15:11         ` Andi Kleen
2008-02-25 15:45           ` James Bottomley
2008-02-25 16:34             ` Andi Kleen
2008-02-24 23:35 ` [PATCH] [13/22] Don't disable direct_io for unchecked_isa_dma in st.c Andi Kleen
2008-02-24 23:35 ` [PATCH] [14/22] Remove automatic block layer bouncing for unchecked_isa_dma Andi Kleen
2008-02-24 23:35 ` [PATCH] [15/22] Remove GFP_DMA use in sr_ioctl Andi Kleen
2008-02-24 23:35 ` [PATCH] [16/22] Remove unchecked_isa_dma from sysfs Andi Kleen
2008-02-24 23:35 ` [PATCH] [17/22] Switch to a single SCSI command pool Andi Kleen
2008-02-24 23:35 ` [PATCH] [18/22] Finally remove unchecked_isa_dma support for Cmnds Andi Kleen
2008-02-24 23:35 ` [PATCH] [19/22] Finally kill unchecked_isa_dma Andi Kleen
2008-02-24 23:35 ` [PATCH] [20/22] Remove GFP_DMA in sr.c Andi Kleen
2008-02-24 23:35 ` [PATCH] [21/22] Remove GFP_DMA in ch.c Andi Kleen
2008-02-24 23:35 ` [PATCH] [22/22] Remove GFP_DMA in sr_vendor.c Andi Kleen

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