hdparm & DMA

Declan Moriarty junk_mail at iol.ie
Fri Aug 19 02:35:47 PDT 2005

Recently, Somebody Somewhere wrote these words
> Hi! I am trying to get dma to work with hdparm (system is VERY slow 
> without it), but when I
> do 'hdparm -d1 /dev/hda' I get this:
> /dev/hda:
> settings using_dma to 1 (on)
> HDIO_SET_DMA failed: Operation not permitted
> using_dma   =   0 (off)
> I am building blfs on top of an LFS 6.0 System. On SuSE dma works fine. 
> How do I fix this?
> Thanks!

Compile in the correct driver for your chipset into the kernel
In config:

Device Drivers / ATA/ATAPI/MFM/RLL support ....

You then don't need generic support, AFAIK,
which is for bog standard chipsets. For me, compiling in via82cxxx moved
performance from ~3 MB/s to ~50 MB/s. 

This may still not do it for you, with certain drives. I found Seagate
ST343xx drives a disaster, and Maxtor ones only would do MDMA (whassat?)

The idea I think was that you load their windows driver and run windows.
Some people get the strangest ideas ever. 


	With best Regards,

	Declan Moriarty.

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