Re: [PATCH] Initialize PIIX3 IDE channels as "enabled"

Avi Kivity
2007-03-13T08:01:16Z

Gregory Haskins wrote:
> This patch initializes the PIIX3 IDE controllers IDE channels as enabled. They were previously unconfigured by QEMU.
>
> IDE devices have been broken on our local lab systems since the introduction of QEMU 0.9.0 (KVM-14). Tracing the Linux driver for PIIX3 initialization revealed that the "enabled" bits (bit 7 in the PCI-CONFIG space at address 0x41 and 0x43, port 0 and 1 respectively) were not set. In a bare-metal system, it would typically be the role of the BIOS to enable something like this, so this solution may be a hack. I speculate that the real bug may be something introduced into Bochs about the same time as the 0.9.0 deployment, but I have not investigated this. Nonetheless, unless there is a specific run-time switch to enable/disable the IDE channels, initializing them in QEMU vs Bochs is probably 6 of one, half dozen of the other.
>
>

Is the bug present in stock qemu-0.9.0?

I'm no acpi expert, but this may be related to our acpi breakage.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.