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[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: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Sergei Shtylyov 2006-12-29 16:49:18 -08:00 committed by Linus Torvalds
parent 755cd90029
commit 242ce41fc9
1 changed files with 0 additions and 31 deletions
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31
drivers/ide/pci/piix.c
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@ -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)
{
switch(hwif->pci_dev->device)
{
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 */