From: Stefan Richter <stefanr@s5r6.in-berlin.de>
To: Julian Calaby <julian.calaby@gmail.com>
Cc: yoma sophian <sophian.yoma@gmail.com>, linux-scsi@vger.kernel.org
Subject: Re: question about passing physical address to lower level driver in scsi
Date: Mon, 31 Oct 2011 13:22:09 +0100 [thread overview]
Message-ID: <20111031132209.1d1ee186@stein> (raw)
In-Reply-To: <CAGRGNgWE4JQ15+Q3rpCvHs_EXiGZ0yu_X9_3FfkrBgsOiXvvLQ@mail.gmail.com>
On Oct 31 Julian Calaby wrote:
> Hi,
>
> On Mon, Oct 31, 2011 at 12:53, yoma sophian <sophian.yoma@gmail.com> wrote:
> > hi stefan:
> > Thanks for your reply.
> > 2011/10/30, Stefan Richter <stefanr@s5r6.in-berlin.de>:
> >> The low level driver, not SCSI core, is responsible to obtain a DMA
> >> address.
> >
> > Why I ask this because I found there is no same transformation for
> > scsi usb subsystem.
> > Would anyone can let me know where it is?
>
> I am not familiar with the code in question, but I would guess that
> this would happen in the USB Controller Interface driver.
I don't know the USB subsystem either. Anyway, in this case the
"SCSI low-level" (i.e. SCSI transport and interconnect driver)
internally consists of USB high-level (storage), USB core, and USB
low-level (UHCI, EHCI or whatever). "grep -r dma_map_sg drivers/usb/"
shows occurrences of scatter-gather list DMA mappings in the USB core. I
haven't checked whether these are indeed the ones that the usb-storage
driver relies on.
--
Stefan Richter
-=====-==-== =-=- =====
http://arcgraph.de/sr/
next prev parent reply other threads:[~2011-10-31 12:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-30 12:05 question about passing physical address to lower level driver in scsi yoma sophian
2011-10-30 12:28 ` Stefan Richter
2011-10-31 1:53 ` yoma sophian
2011-10-31 6:11 ` Julian Calaby
2011-10-31 12:22 ` Stefan Richter [this message]
2011-10-31 12:28 ` yoma sophian
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