From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: PATA DMA problem leading to kernel panic on reading movie DVDs Date: Tue, 19 May 2009 23:31:59 +0200 Message-ID: <200905192332.00707.bzolnier@gmail.com> References: <20090517091224.GA8280@wanza.invalid> <200905192131.00168.bzolnier@gmail.com> <20090519211221.GA6977@wanza.invalid> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bw0-f174.google.com ([209.85.218.174]:51814 "EHLO mail-bw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752578AbZESVbc (ORCPT ); Tue, 19 May 2009 17:31:32 -0400 In-Reply-To: <20090519211221.GA6977@wanza.invalid> Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Martin Lottermoser Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org On Tuesday 19 May 2009 23:12:21 Martin Lottermoser wrote: > Hi, > > On Tue, May 19, 2009 at 09:30:59PM +0200, Bartlomiej Zolnierkiewicz wrote: > > Incremental patch fixing it: > > > > diff -u b/drivers/ide/ide-iops.c b/drivers/ide/ide-iops.c > > --- b/drivers/ide/ide-iops.c > > +++ b/drivers/ide/ide-iops.c > > @@ -255,7 +255,7 @@ > > if (ivb) { > > const char *model = (char *)&id[ATA_ID_PROD]; > > > > - if (strcmp("TSSTcorp CDDVDW SH-S202", model) == 0) { > > + if (strstr("TSSTcorp CDDVDW SH-S202", model)) { > > /* > > * These ATAPI devices always report 80c cable > > * so we have to depend on the host in this case. > > > > I applied that, recompiled, installed, rebooted, and checked the syslog. > The message was still > > hdc: UDMA/66 mode selected > > and hdparm also showed "udma4" as being selected. I therefore didn't test > with a DVD. > > However, after twice reading the POSIX definition of strstr() I reversed > the order of the arguments to > > if (strstr(model, "TSSTcorp CDDVDW SH-S202")) { /me hides > and that did it. Syslog now contained: > > hdc: host side 80-wire cable detection failed, limiting max speed to UDMA33 > hdc: UDMA/33 mode selected > > hdparm showed "udma2", and playing movie DVDs worked without DMA being > disabled. :-) :) The final patch version: From: Bartlomiej Zolnierkiewicz Subject: [PATCH] ide: fix 40-wire cable detection for TSST SH-S202* ATAPI devices (v2) Since 2.6.26 we support UDMA66 on ATAPI devices requiring IVB quirk: commit 8588a2b732928b343233af9b1855705b8286bed4 ("ide: add SH-S202J to ivb_list[]") We also later added support for more such devices in: commit e97564f362a93f8c248246c19828895950341252 ("ide: More TSST drives with broken cable detection") and in: commit 3ced5c49bd2d1f2c7f769e3a54385883de63a652 ("ide: add TSSTcorp CDDVDW SH-S202H to ivb_list[]") It turns out that such devices lack cable detection altogether (which in turn results in incorrect detection of 40-wire cables by our current cable detection strategy) so always handle them by trusting host-side cable detection only. v2: Model detection fixup from Martin. Reported-and-tested-by: Martin Lottermoser Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/ide-iops.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) Index: b/drivers/ide/ide-iops.c =================================================================== --- a/drivers/ide/ide-iops.c +++ b/drivers/ide/ide-iops.c @@ -206,8 +206,6 @@ EXPORT_SYMBOL_GPL(ide_in_drive_list); /* * Early UDMA66 devices don't set bit14 to 1, only bit13 is valid. - * We list them here and depend on the device side cable detection for them. - * * Some optical devices with the buggy firmwares have the same problem. */ static const struct drive_list_entry ivb_list[] = { @@ -251,10 +249,25 @@ u8 eighty_ninty_three(ide_drive_t *drive * - force bit13 (80c cable present) check also for !ivb devices * (unless the slave device is pre-ATA3) */ - if ((id[ATA_ID_HW_CONFIG] & 0x4000) || - (ivb && (id[ATA_ID_HW_CONFIG] & 0x2000))) + if (id[ATA_ID_HW_CONFIG] & 0x4000) return 1; + if (ivb) { + const char *model = (char *)&id[ATA_ID_PROD]; + + if (strstr(model, "TSSTcorp CDDVDW SH-S202")) { + /* + * These ATAPI devices always report 80c cable + * so we have to depend on the host in this case. + */ + if (hwif->cbl == ATA_CBL_PATA80) + return 1; + } else { + /* Depend on the device side cable detection. */ + if (id[ATA_ID_HW_CONFIG] & 0x2000) + return 1; + } + } no_80w: if (drive->dev_flags & IDE_DFLAG_UDMA33_WARNED) return 0;