> It isn't clear to me whether the device is recognized by libata > ata_piix, or just by a separate kernel IDE Intel PIIX driver? One slot by each - CD by old IDE disk by libata in the dump you gave > [<c025d0ae>] (ide_intr+0x0/0x11e) > Disabling IRQ #185 and old IDE broke No kernel that old supports the needed workarounds for the ICH behaviour change. Intel changed the ICH behaviour on IRQ handling in the later chips in some configurations that are mostly used on the mac. The SATA backport in Centos 4.x doesn't include the needed changes nor does the IDE layer. Ditto I believe 5.x. You need to use the current IRQ clearing logic for both drivers - the old logic only clears the ata status register on PIO events, the newer one clears both the ata and DMA status to work around the Intel funny. [By a strict reading of the spec the Intel behaviour does appear allowed, although I hope Intel didn't intend it ...] Alan -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
