Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264938AbUD2Tck (ORCPT ); Thu, 29 Apr 2004 15:32:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264936AbUD2Tck (ORCPT ); Thu, 29 Apr 2004 15:32:40 -0400 Received: from mion.elka.pw.edu.pl ([194.29.160.35]:11220 "EHLO mion.elka.pw.edu.pl") by vger.kernel.org with ESMTP id S264935AbUD2TcQ (ORCPT ); Thu, 29 Apr 2004 15:32:16 -0400 From: Bartlomiej Zolnierkiewicz To: Patrick Wildi Subject: Re: [RFC][PATCH] 2.4 IDE Serverworks OSB4 DMA patch Date: Thu, 29 Apr 2004 21:32:26 +0200 User-Agent: KMail/1.5.3 Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, andre@linux-ide.org References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200404292132.26039.bzolnier@elka.pw.edu.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2823 Lines: 81 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. > - 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). ;) > 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/