From: Grant Grundler <grundler@parisc-linux.org>
To: "Stephen C. Tweedie" <sct@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Ranjith Sudarsanan <ranjith_sudarsanan@hp.com>,
"parisc-linux@lists.parisc-linux.org"
<parisc-linux@lists.parisc-linux.org>
Subject: Re: [Fwd: [parisc-linux] Problems with raw interface.]
Date: Sat, 20 Sep 2003 18:27:33 -0600 [thread overview]
Message-ID: <20030921002733.GE31268@dsl2.external.hp.com> (raw)
In-Reply-To: <1063989244.2834.48.camel@sisko.scot.redhat.com>
On Fri, Sep 19, 2003 at 05:34:04PM +0100, Stephen C. Tweedie wrote:
> > > But when I use the raw interface I get garbage. For instance please
> > > look at the output below. I am reading the 1st sector of the disk,
> > > which is the boot sector, When I use the block device /dev/sda I get
> > > my expected output, whereas when I use the raw interface I get
> > > garbage. Can any one explain? The machine I am using is an L Class.
>
> Do you _ever_ get valid output, or is raw always failing? There may
> well be a cache coherency point being missed.
I was able to consistently reproduce this problem on a c3000 (400Mhz
PA8500). That's running 2.4.22 kernel.
> The key places are rw_raw_dev(), where we set up the virtual address to
> physical page mappings, and brw_kiovec(), where the actual physical page
> IO is done.
ok - I should try again with 2.6 kernel and look again.
But I'm certainly no vm/cache expert.
grant
next prev parent reply other threads:[~2003-09-21 0:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1063919293.16536.2.camel@dhcp23.swansea.linux.org.uk>
2003-09-19 16:34 ` [Fwd: [parisc-linux] Problems with raw interface.] Stephen C. Tweedie
2003-09-21 0:27 ` Grant Grundler [this message]
2003-09-21 5:35 ` Grant Grundler
2003-09-21 14:25 ` Matthew Wilcox
2003-09-22 5:00 ` Grant Grundler
2003-09-22 10:47 ` Stephen C. Tweedie
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