Re: Cannot enable DMA on SATA drive (SCSI-libsata, VIA SATA)

[Petr Sebor]

Petter Sundlöf wrote:
> Using 2.6.8.1. DMA works fine on /dev/hda (PATA, CD burner).
>
> When I try to enable it for my SATA drive (which is performing horribly 
> bad -- 80-90% CPU load on an AMD64 3200+ during copy of large files)

Hello,

just a 'me too' e-mail... I have Master2-FAR mobo, VIA/KT800 chipset.
IDE disk runs like a charm but SATA disks consume big amount of cpu
time (which is spent in iowait). The system behaves exactly as with
old IDE disk and DMA disabled... everything is slow when data is 
transferred to/from disk.

I have played with various settings, io schedulers, acpi... but haven't
found anything useful so far..

Regards,
Petr
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