Messages in this thread | | | Date | Thu, 29 Apr 2004 15:09:47 -0700 (PDT) | From | Patrick Wildi <> | Subject | Re: [RFC][PATCH] 2.4 IDE Serverworks OSB4 DMA patch |
| |
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/
| |