Commit 242ce41f authored by Sergei Shtylyov's avatar Sergei Shtylyov Committed by Linus Torvalds

[PATCH] PIIX: remove check for broken MW DMA mode 0

There's no need to check in piix_config_drive_for_dma() for broken MW DMA
mode 0 as this mode is not supported by the driver (it sets
hwif->mwdma_mask to 0x6), and hence can't be selected by ide_dma_speed().

(Alan sayeth "Probably right but if not you've got a subtle corruptor.  Should
at least stick a BUG_ON mode 0 setting right close when the mode is set.")
Signed-off-by: default avatarSergei Shtylyov <>
Cc: Alan Cox <>
Acked-by: default avatarBartlomiej Zolnierkiewicz <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 755cd900
......@@ -352,33 +352,6 @@ static int piix_tune_chipset (ide_drive_t *drive, u8 xferspeed)
return (ide_config_drive_speed(drive, speed));
* piix_faulty_dma0 - check for DMA0 errata
* @hwif: IDE interface to check
* If an ICH/ICH0/ICH2 interface is is operating in multi-word
* DMA mode with 600nS cycle time the IDE PIO prefetch buffer will
* inadvertently provide an extra piece of secondary data to the primary
* device resulting in data corruption.
* With such a device this test function returns true. This allows
* our tuning code to follow Intel recommendations and use PIO on
* such devices.
static int piix_faulty_dma0(ide_hwif_t *hwif)
case PCI_DEVICE_ID_INTEL_82801AA_1: /* ICH */
case PCI_DEVICE_ID_INTEL_82801AB_1: /* ICH0 */
case PCI_DEVICE_ID_INTEL_82801BA_8: /* ICH2 */
case PCI_DEVICE_ID_INTEL_82801BA_9: /* ICH2 */
return 1;
return 0;
* piix_config_drive_for_dma - configure drive for DMA
* @drive: IDE drive to configure
......@@ -391,10 +364,6 @@ static int piix_faulty_dma0(ide_hwif_t *hwif)
static int piix_config_drive_for_dma (ide_drive_t *drive)
u8 speed = ide_dma_speed(drive, piix_ratemask(drive));
/* Some ICH devices cannot support DMA mode 0 */
if(speed == XFER_MW_DMA_0 && piix_faulty_dma0(HWIF(drive)))
speed = 0;
/* If no DMA speed was available or the chipset has DMA bugs
then disable DMA and use PIO */
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