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

From: Chris Li
Date: Tue Jun 29 2010 - 21:07:17 EST

On Tue, Jun 29, 2010 at 4:57 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>> 0000:00:0f.0: ioat2_timer_event: Channel halted (10)
> This says that we got an invalid chain address error when trying to start
> the engine.  If there was a driver problem with init I would have expected
> to see reports from other systems.  The attached patch will print out what
> chain address we are setting.  The hardware expects a 64-byte aligned
> address which should be guaranteed by the use of pci_pool_alloc().

OK. I can't do this test remotely so I will get back to you tomorrow.

> However, if you are up for another experiment, I'd like to see what happens
> if you disable VT-d.  Maybe it is a misconfigured iommu table that is
> blocking the engine's access to memory?

You mean disable VT-d in kernel config or the BIOS?

BTW, I don't know how to disable VT-d in Mac BIOS. It use EFI, then simulate
a normal BIOS in the boot camp mode to boot Linux.

Another stab in the dark is that, it is Mac. It has some strange SMI interaction
like TSC drifting even after boot. I notice that in the past.

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