Messages in this thread Patch in this message | | | Date | Thu, 29 Apr 2004 12:04:13 -0700 (PDT) | From | Patrick Wildi <> | Subject | [RFC][PATCH] 2.4 IDE Serverworks OSB4 DMA patch |
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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; }
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