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

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

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.


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