From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sat, 20 Sep 2003 18:27:33 -0600 From: Grant Grundler To: "Stephen C. Tweedie" Cc: Alan Cox , Ranjith Sudarsanan , "parisc-linux@lists.parisc-linux.org" Subject: Re: [Fwd: [parisc-linux] Problems with raw interface.] Message-ID: <20030921002733.GE31268@dsl2.external.hp.com> References: <1063919293.16536.2.camel@dhcp23.swansea.linux.org.uk> <1063989244.2834.48.camel@sisko.scot.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1063989244.2834.48.camel@sisko.scot.redhat.com> Sender: parisc-linux-admin@lists.parisc-linux.org Errors-To: parisc-linux-admin@lists.parisc-linux.org List-Help: List-Post: List-Subscribe: , List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: 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