Re: PATCH: Fix broken PIO with libata

From: Kevin Radloff
Date: Tue May 16 2006 - 13:18:39 EST

On 5/16/06, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
On Maw, 2006-05-16 at 11:33 -0400, Kevin Radloff wrote:
> However, I still have a problem with pata_pcmcia (that I actually
> experienced also with the ide-cs driver) where sustained reading or
> writing to the CF card spikes the CPU with nearly 100% system time.

That is normal. The PCMCIA devices don't support DMA. As a result of
this the processor has to fetch each byte itself over the ISA speed
PCMCIA bus link.

Hrm, as I recall that only started happening with ide-cs sometime in
the single digits of 2.6.x.. And note that it's only maxing out at
about 1.5MB/s. Should that saturate my laptop's 1.1GHz Pentium M

Kevin 'radsaq' Radloff
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at