Re: [Q] PCI Express and ide (native) leads to irq storm?

From: Jeff Garzik
Date: Wed Nov 15 2006 - 13:50:00 EST


Tejun Heo wrote:
In short, some piix controllers including ICH7, when put into enhanced mode (PCI native mode), uses BMDMA Interrupt bit as interrupt pending/clear bit for *all* commands. ie. Reading STATUS does NOT clear

Yep. I thought I had mentioned this, ages ago.


Fortunately, libata is immune to the problem because it does ap->ops->irq_clear(ap) in ata_host_intr() regardless of command type in flight. So, not loading IDE piix and using libata to drive all piix ports solves the problem.

Yep, that's intentional :)

Jeff



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