Re: [PATCH] mips: sb1250_swarm_defconfig: disable IDE subsystem

From: Sergei Shtylyov
Date: Mon Nov 09 2015 - 14:08:38 EST

On 11/09/2015 09:54 PM, Maciej W. Rozycki wrote:

I think I've been reasonably serious about my SWARM and despite issues
elsewhere the onboard PATA interface is a part of the system I've never
had any with. Yes, it's limited to PIO 3, but it's not a big deal, that's
still 11MB/s (and one of the 4 generic data movers present in the SoC

If you measure it with something like 'hdparm -t', the real speed figures
in the PIO modes would disappoint you. It's usually more like 3 MB/s even in

Well, various factors contribute to actual figures possible to achieve,
the physical medium transfer speed being an important one.

Yes, of course. Yet even with MWDMA2 (same wire speed as PIO4) hdparm shows about an order of magnitude higher speeds, IIRC. With the UltraDMA modes it becomes even higher...

That 11MB/s
throughput is the maximum you can ever get on the wire in PIO 3, assuming
data is already available to transfer and IORDY is asserted right away
every cycle.

Yes, I figured.



MBR, Sergei

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