[ale] boot parms ide=???

[Michael D. Hirsch]

On Thursday 20 February 2003 10:37 am, Danny Cox wrote:
> Marvin,
>
> On Wed, 2003-02-19 at 06:16, Marvin Dickens wrote:
> > hdparm -c1 -m16 -d1 /dev/hda
> >
> > This enables 32bit access and multisector reads. These items may
> > already be present in a compiled kernel. It depends on distro.
>
> 	Just one little nit to pick.  The man pages don't say this, only code
> inspection will reveal this.
>
> 	If you're using DMA, then -c{01} doesn't matter.  That only affects PIO
> transfers (16 bit words or 32 bit words), so by all means, if you're
> stuck with PIO, use -c1!

I'm glad to hear someone else say this.  I've long suspected this to be the 
case both for theoretical and experimental reasons.  Code inspection is 
probably an even better reason.

> 	The same is true for -mN.  The code has different paths depending on
> whether it's transferring single or multiple sectors.  However, when DMA
> is in use, that's all bypassed, and the multisector stuff is handled by
> the scatter/gather DMA code.

Didn't know this, but it makes sense and is good to know.

Thanks,

Michael

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