Re: kernel: Bogus pci_unmap_single: dma_addr 0 base 800000 size 800000

[Jay Estabrook <Jay Estabrook hp com>]

On Wed, Dec 10, 2003 at 09:53:34AM +0100, Helge Kreutzmann wrote:
> 
> since we had a spare SCSI disk lying around (and I have no idea where
> I should get the appropriate containers for the nice drive bays the
> rawhide has) we added another SCSI adapter to our SMP rawhide. An
> external MO drive works fine, but during access of the attaced drive we
> see lots of
> 
> kernel: Bogus pci_unmap_single: dma_addr 0  base 800000 size 800000
> 
> The controller is an "Adaptec AHA-2940U2/W". The relevant code is in
> arch/alpha/kernel/pci_iommu.c
> and looks like:
>         if (dma_ofs * PAGE_SIZE >= arena->size) {
>                 printk(KERN_ERR "Bogus pci_unmap_single: dma_addr %lx "
>                        " base %lx size %x\n", dma_addr, arena->dma_base,
>                        arena->size);
>                 return;
>                 BUG();
>         }
> (this is 2.4.21). This looks like a know BUG(). Is this harmless or is
> there a workaround available?

It *may* be harmless, in the case where direct-map was used for DMA.

The "dma_addr" passed in (0 in this case) is not a valid address for
either direct-map or scatter-gather-map DMA, and indicates something
may have gone wrong in the driver.

But, this doesn't explain why the MO drive worked and the HDD doesn't...

If your RAWHIDE has more than 2GB of memory, then it most likely WILL
be a problem at some point.

So, what Adaptec driver was used, and what did it report for the chipset?

 --Jay++

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Jay A Estabrook                            HPTC - LINUX support
Hewlett-Packard Company - MRO1-2/K15       (508) 467-2080
200 Forest Street, Marlboro MA 01752       Jay Estabrook hp com
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