Re: 2.1.111: IDE DMA disabled?

Gadi Oxman (
Wed, 25 Mar 1998 22:22:18 +0300 (IST)

On 25 Jul 1998, Linus Torvalds wrote:

> In article <>,
> John Hayward-Warburton <> wrote:
> >
> >Saw in drivers/block/ that IDE DMA code was buggy and had
> >not been enabled in 2.1.111. I must confess to having seen no
> >problems on this machine (can't remember whether it's HX or TX
> >Intel chipset), Quantum Fireball SE 8.4A using Ultra-DMA on /dev/hdc
> >and an older Seagate ST32140A on /dev/hda, Intel P233MMX, Gigabyte
> >GA-586TX2 m/b, no SCSI anywhere.
> >
> >Was this intentional? hacked here to enable DMA again.
> It was very much intentional.
> People claim that the DMA problems may be due to having IDE cables of
> bad quality or too long for the spec. HOWEVER, that claim misses the
> point: even if the cable is bad it's not ok to have silent corruption,
> so there is something wrong with the driver with DMA enabled. The newer
> IDE standards are supposed to have CRC checks, and obviously they aren't
> triggering for some reason.
> This I disabled DMA until somebody can tell me what is up, rather than
> just suggest people try shorter cables.
> Linus

The configuration on which the filesystem corruption was observed is a
Tyan Tomcat III board + WD 2.2GB drive; that motherboard is using the
430HX chipset, which pre-dates Ultra-DMA and doesn't support CRC check.


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