From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Oskar Liljeblad" Subject: clock drift with 2x Promise Ultra133 TX2 (PDC 20269) (again) Date: Tue, 24 May 2005 18:53:39 +0200 Message-ID: <20050524165339.GA16577@oskar> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from diadema.skane.tbv.se ([193.13.139.13]:14055 "EHLO diadema.skane.tbv.se") by vger.kernel.org with ESMTP id S261349AbVEXQxm (ORCPT ); Tue, 24 May 2005 12:53:42 -0400 Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Cc: raw@dslr.net Problem: I have two Promise Ultra133 TX2 (PDC 20269) cards, each with two Maxtor UDMA133 hard drives connected. The system also has another hard drive connected to the motherboard. A total of five drives. When I concurrently read from two hard drives connected to different Promise cards, there is heavy software clock drift. The software clock runs too fast - approx. a few seconds per minute during this i/o. To reproduce: hwclock --hctosys hwclock --show date dd if=/dev/hde of=/dev/null bs=1M count=7200 & dd if=/dev/hdi of=/dev/null bs=1M count=7200 & wait wait hwclock --show date This doesn't happen if I read from two drives connected to the same card, or one drive connected to the motherboard and one connected to a Promise card. I've removed all other PCI devices in the system - problem remains. I tried different motherboards: Asus A7V266-C with AMD AthlonXP 2000+ (i686) - problem occurs Asus A7V600-X with AMD Sempron 2600+ (i686) - problem occurs Abit KV8 Pro with AMD Athlon64 3000+ (i686) - problem does not occur! So what makes the Abit motherboard different? Regards, Oskar Liljeblad (oskar@osk.mine.nu)