Re: ICH5 SATA causes high interrupt/system load?

From: Jeff Garzik (
Date: Tue Jul 01 2003 - 15:41:25 EST

Jurgen Kramer wrote:
> Hi,
> After reading about problems with ICH5 SATA (Intel 875P) I've
> set my BIOS back to normal mode for the SATA controller. So now the SATA
> drive appears as hdc instead of hde.
> The SATA drive was working in both situations (enhanced/normal) the only
> difference is that with normal mode there no high system load caused by
> the SATA controller (As I reported in a previous mail).
> What's causing the high interrupt count in 'enhanced' mode?

Well, in legacy mode (a.k.a. normal), each ATA port (a.k.a. channel
a.k.a. bus) gets their own interrupt, which is never shared with another

In native mode (a.k.a. enhanced), two ATA ports share a single PCI
interrupt. Further, this interrupt may be shared with any number of
other PCI devices.

So, high interrupt count is necessarily a worry because you're probably
seeing a coalescing of multiple interrupt counts into one big one.


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