Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264840AbUD2TEe (ORCPT ); Thu, 29 Apr 2004 15:04:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264921AbUD2TEe (ORCPT ); Thu, 29 Apr 2004 15:04:34 -0400 Received: from bern.wildisoft.net ([66.80.62.108]:42769 "EHLO bern.wildisoft.net") by vger.kernel.org with ESMTP id S264840AbUD2TER (ORCPT ); Thu, 29 Apr 2004 15:04:17 -0400 Date: Thu, 29 Apr 2004 12:04:13 -0700 (PDT) From: Patrick Wildi X-X-Sender: patrick@bern.wildisoft.net To: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org cc: andre@linux-ide.org, B.Zolnierkiewicz@elka.pw.edu.pl Subject: [RFC][PATCH] 2.4 IDE Serverworks OSB4 DMA patch Message-ID: 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: 2434 Lines: 68 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. - 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. 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. 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/