From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Hancock Subject: Re: Question with AHCI and (UDMA/100 vs. UDMA/133) Date: Tue, 30 Dec 2008 11:34:15 -0600 Message-ID: <495A5B97.4040202@shaw.ca> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from main.gmane.org ([80.91.229.2]:55662 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751712AbYL3Ree (ORCPT ); Tue, 30 Dec 2008 12:34:34 -0500 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1LHiU8-0003R7-19 for linux-ide@vger.kernel.org; Tue, 30 Dec 2008 17:34:28 +0000 Received: from s0106000c41bb86e1.ss.shawcable.net ([70.76.47.20]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 30 Dec 2008 17:34:28 +0000 Received: from hancockr by s0106000c41bb86e1.ss.shawcable.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 30 Dec 2008 17:34:28 +0000 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org Cc: linux-kernel@vger.kernel.org Justin Piszcz wrote: > Do some chipsets (SiI 3132 vs. Intel ICH9) run certain drives at > UDMA/100 vs. UDMA/133? On native SATA drives and controllers, the UDMA speed really has no effect. At the low level there are just frames going back and forth on the link at either 1.5 or 3.0 Gbps so the UDMA speed doesn't really control anything. If there is a PATA bridge involved (either internal or external to the drive) then this can affect the speed on the PATA bus, but that won't be the case here (NCQ support wouldn't be possible in that case). > > I have several 750GB WD drives (exact make/model) and the ones on the > intel chipset show up as: > > [ 1.407321] ata3.00: ATA-7: WDC WD7500AAKS-00RBA0, 30.04G30, max > UDMA/133 > [ 1.407409] ata3.00: 1465149168 sectors, multi 0: LBA48 NCQ (depth > 31/32) > [ 1.408300] ata3.00: configured for UDMA/133 > > The ones on the SiI 3132 chipset show up as: > > [ 9.604413] ata11: SATA link up 3.0 Gbps (SStatus 123 SControl 0) > [ 9.619024] ata11.00: ATA-7: WDC WD7500AAKS-00RBA0, 30.04G30, max > UDMA/133 > [ 9.619111] ata11.00: 1465149168 sectors, multi 16: LBA48 NCQ (depth > 31/32) > [ 9.620029] ata11.00: configured for UDMA/100 > > If they are both 3.0 Gbps, are they both the same speed even though one > is configured for a slower speed than the other? Yes. > > Or is it the case that the SiI 3132 does not support AHCI and that is > the reason for the difference? Does it make any difference in performance? 3132 is not an AHCI controller but it still supports most or all of the same features. (AHCI is not a feature set, it's a particular hardware interface.) > > SiI Controller: > 02:00.0 RAID bus controller: Silicon Image, Inc. SiI 3132 Serial ATA > Raid II Controller (rev 01) > > Intel Controller: > 00:1f.2 SATA controller: Intel Corporation 82801IR/IO/IH (ICH9R/DO/DH) 6 > port SATA AHCI Controller (rev 02) > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ide" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >