Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264994AbUD2WL2 (ORCPT ); Thu, 29 Apr 2004 18:11:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264996AbUD2WL1 (ORCPT ); Thu, 29 Apr 2004 18:11:27 -0400 Received: from bern.wildisoft.net ([66.80.62.108]:51205 "EHLO bern.wildisoft.net") by vger.kernel.org with ESMTP id S264993AbUD2WJ7 (ORCPT ); Thu, 29 Apr 2004 18:09:59 -0400 Date: Thu, 29 Apr 2004 15:09:47 -0700 (PDT) From: Patrick Wildi X-X-Sender: patrick@bern.wildisoft.net To: Bartlomiej Zolnierkiewicz cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, andre@linux-ide.org Subject: Re: [RFC][PATCH] 2.4 IDE Serverworks OSB4 DMA patch In-Reply-To: <200404292132.26039.bzolnier@elka.pw.edu.pl> Message-ID: References: <200404292132.26039.bzolnier@elka.pw.edu.pl> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3573 Lines: 98 On Thu, 29 Apr 2004, Bartlomiej Zolnierkiewicz wrote: > On Thursday 29 of April 2004 21:04, Patrick Wildi wrote: > > I have been using a OSB4 chipset based system with a CompactFlash > > that supports PIO only and a laptop IBM/Hitachi Travelstar HDD > > that supports UDMA. > > For both drives, the serverworks code misconfigures the drives: > > > > - for the CF (hooked up as /dev/hda), svwks_config_drive_xfer_rate() > > will not match any tests (drive->autodma = 0, id->capability = 2, > > id->field_valid = 1), but the function will then call > > hwif->ide_dma_on(drive), which it should not do for this drive. > > This patch moves the enabling of DMA up into the DMA section of > > the code. > > Yep, known bug, it is fixed in 2.6. > > It is present in many other drivers, my 2.6 patch needs to be backported. Are you the maintainer for 2.4 or to whom should I send the changes? > > - for the Travelstart HDD, the settings coming into > > svwks_config_drive_xfer_rate() are: drive->autodma = 32, > > id->capability = 15, id->field_valid = 7, id->dma_ultra = 0x43f. > > But as this is an OSB4, the hwif->ultra_mask is set to not support > > UDMA. Unfortunately in that case svwks_config_drive_xfer_rate() > > falls through to the end of the function, instead of trying > > other DMA modes. > > Good catch. > > It seems the same bug can be present in other drivers too (hint, hint). ;) I noticed that the piix driver uses the exact same logic. I could replicate this part of the patch for other 2.4 drivers. I have no way of testing them. I can send you a combined patch for 2.4. I am not yet using 2.6. Patrick > > By adding a jump to try_dma_modes in the case that the drive > > is UDMA capable but the mask does not allow UDMA, the drive > > will be setup up for MWDMA. > > > > The logic in svwks_config_drive_xfer_rate() could probably be > > improved a bit, but I kept the changes to an absolute minium > > to reduce the risk of breakage. > > OK, thanks. > > > The patch is against 2.4.24, but the file has not changed in > > 2.4.25 and 2.4.26. > > > > Patrick > > > > > > --- linux-2.4.24-nam/drivers/ide/pci/serverworks.c.orig Thu Apr 22 17:31:28 > > 2004 +++ linux-2.4.24-nam/drivers/ide/pci/serverworks.c Thu Apr 29 11:02:05 > > 2004 @@ -473,7 +473,9 @@ > > int dma = config_chipset_for_dma(drive); > > if ((id->field_valid & 2) && !dma) > > goto try_dma_modes; > > - } > > + } else > > + /* UDMA disabled by mask, try other DMA modes */ > > + goto try_dma_modes; > > } else if (id->field_valid & 2) { > > try_dma_modes: > > if ((id->dma_mword & hwif->mwdma_mask) || > > @@ -490,6 +492,7 @@ > > } else { > > goto no_dma_set; > > } > > + return hwif->ide_dma_on(drive); > > } else if ((id->capability & 8) || (id->field_valid & 2)) { > > fast_ata_pio: > > no_dma_set: > > @@ -497,7 +500,7 @@ > > // hwif->tuneproc(drive, 5); > > return hwif->ide_dma_off_quietly(drive); > > } > > - return hwif->ide_dma_on(drive); > > + return 0; > > } > > > > /* This can go soon */ > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/