Re: BUG in drivers/dma/ioat/dma_v2.c:314

[Dan Williams]

On 7/1/2010 12:12 AM, Woodhouse, David wrote:
> On Thu, 2010-07-01 at 07:51 +0100, Williams, Dan J wrote:
> > This version of the device only exists on the 5400 chipset and always
> > has its own iommu, but since other platforms get the DMAR entry right I
> > think this hammer is too big?  Wouldn't this break VT-d operation on
> > non-busted platforms?
>
> That just means we have to get the quirk right. Does 'this version' of
> the device have its own PCI ID? We can always fall back to checking the
> ID of the device at 0000:00:00.0 to check which chipset we're on.

PCI_DEVICE_ID_INTEL_IOAT_SNB only exists on this chipset and to date 
only "MacPro3,1" platforms have this problem.

> > Alternatively I can just catch this failure earlier in the init process
> > and fail the driver load with a grumble printk about broken bios...
> > instead of the current BUG_ON() that is meant to catch runtime catastrophes.
>
> Please use WARN_TAINT(TAINT_FIRMWARE_WORKAROUND). That way the
> statistics end up in kerneloops.org and we have found that extremely
> useful when LARTing the offending vendors.

Good to know, thanks.

--
Dan
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