From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 26 Nov 2002 07:58:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 26 Nov 2002 07:58:25 -0500 Received: from louise.pinerecords.com ([212.71.160.16]:54029 "EHLO louise.pinerecords.com") by vger.kernel.org with ESMTP id ; Tue, 26 Nov 2002 07:58:24 -0500 Date: Tue, 26 Nov 2002 14:05:38 +0100 From: Tomas Szepe To: Adrian Bunk Cc: Dennis Grant , linux-kernel@vger.kernel.org Subject: Re: Identifying/activating faster ATAxx modes (WAS kernel config tale of woe) Message-ID: <20021126130538.GM29196@louise.pinerecords.com> References: <3de2eee3.16fd.0@wincom.net> <20021126034900.GB29196@louise.pinerecords.com> <20021126121329.GI24796@fs.tum.de> <20021126121545.GL29196@louise.pinerecords.com> <20021126124846.GK24796@fs.tum.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20021126124846.GK24796@fs.tum.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > > > > /dev/hda: > > > > > > > > > > Model=Maxtor 6E030L0, FwRev=NAR61590, SerialNo=E106SZLE > > > > > Config={ Fixed } > > > > > RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57 > > > > > BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=16 > > > > > CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=60058656 > > > > > IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} > > > > > PIO modes: pio0 pio1 pio2 pio3 pio4 > > > > > DMA modes: mdma0 mdma1 mdma2 > > > > > UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 > > > >... > > > > This is weird. Your disk seems to be set up for udma6 (UATA133), > > > > which should provide for transfer rates of at least 40MiB/s. > > > >... > > > > > > The information in "hdparm -i" shows the identification info of the > > > drive. It doesn't show whether DMA is actually used (you need > > > "hdparm -v" for this)... > > > > While this is true, I fail to see why the -i output would report > > udma6 as being the current transfer mode instead of a pio one if > > DMA were disabled. > > These were my thoughts until someone told me some time ago that this is > wrong... > > 1. "man hdparm" says: "-i Display the identification info that > was obtained from the drive at _boot time_", it doesn't give > information about the current state of the drive. > > 2. Try to disable DMA using "hdparm -d0" (you can check it with > "hdparm -v") - the information displayed by "hdparm -i" won't > change. Hmm, I wasn't aware of this. The manpage confirms what you're saying and adds that the information may or may not be reflecting the current state. However, Dennis's -I output also shows udma6 as the mode the drive is in, and -I info -- according to the manual -- is obtained "directly from the drive," which I read as "let's ask the drive what it's set up like at this moment." Dennis, could you possibly post the "hdparm -v" output too? -- Tomas Szepe