From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Hancock Subject: Re: libata: ATA exception error messages in pata_sch module (CONFIG_PATA_SCH) Date: Tue, 01 Mar 2011 18:59:48 -0600 Message-ID: <4D6D9684.505@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-qw0-f46.google.com ([209.85.216.46]:55509 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757226Ab1CBA7v (ORCPT ); Tue, 1 Mar 2011 19:59:51 -0500 Received: by qwd7 with SMTP id 7so4158961qwd.19 for ; Tue, 01 Mar 2011 16:59:50 -0800 (PST) In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Kushal Koolwal Cc: "David S. Miller" , Borislav Petkov , linux-ide@vger.kernel.org On 03/01/2011 05:17 PM, Kushal Koolwal wrote: > I see the following group of exception messages (repeated 5 times) > when a IDE CD-ROM is present along with IDE hard drive on this Intel > Atom/Menlow system: > > [ 4.278671] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 > [ 4.278769] ata1.00: BMDMA stat 0x64 > [ 4.278856] ata1.00: failed command: READ DMA > [ 4.278950] ata1.00: cmd c8/00:20:70:ca:ab/00:00:00:00:00/e0 tag 0 > dma 16384 in > [ 4.278953] res 51/84:00:8f:ca:ab/00:00:00:00:00/e0 Emask > 0x10 (ATA bus error) > [ 4.279238] ata1.00: status: { DRDY ERR } > [ 4.279322] ata1.00: error: { ICRC ABRT } > [ 4.279429] ata1: soft resetting link > [ 4.656816] ata1.00: configured for UDMA/100 > [ 4.688263] ata1.01: configured for UDMA/33 > [ 4.689038] ata1: EH complete > [ 4.703657] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 > [ 4.703749] ata1.00: BMDMA stat 0x64 > [ 4.703834] ata1.00: failed command: READ DMA > [ 4.703928] ata1.00: cmd c8/00:20:70:ca:ab/00:00:00:00:00/e0 tag 0 > dma 16384 in > [ 4.703931] res 51/84:00:8f:ca:ab/00:00:00:00:00/e0 Emask > 0x10 (ATA bus error) > [ 4.704163] ata1.00: status: { DRDY ERR } > [ 4.704249] ata1.00: error: { ICRC ABRT } > [ 4.704355] ata1: soft resetting link > [ 5.081245] ata1.00: configured for UDMA/100 > [ 5.112262] ata1.01: configured for UDMA/33 > [ 5.113026] ata1: EH complete > > The system does boot fine ultimately and hdparm reports the correct > max. UDMA mode permissible on the system which is UDMA2 in this case. > The system uses 40 conductor cable. I do not see the above exception > messages when only IDE hard drive is present. > > Giving the parameter libata.force=40c gets rid of these messages. You shouldn't really use a 40-conductor cable in a system that has devices that support faster than UDMA mode 2. Normally the kernel would detect the 40-wire cable and block using faster speeds, but it seems like the pata_sch driver doesn't support cable detection as the cable_detect method is set to ata_cable_unknown (either because the hardware doesn't support it or the author didn't bother to implement it), so it can't detect this automatically. It's possible that it works without the CD-ROM drive since there is less electrical noise, etc. with only one device on the cable. > > Attaching dmesg and lspci -vvvxxx output when both an IDE CD-ROM and > hard drive is present. I noticed that the D0TIM Bit30 (PPE) and D0TIM > Bit31 (USD) are both set by Linux kernel in the PCI config space of > the IDE controller. > > Please let me know what other information I can provide in this regards. > > Kushal Koolwal