Panic in quirk_usb_early_handoff

[Mason]

On 06/03/2017 16:27, David Laight wrote:

> Mason wrote:
>>
>>> So the kernel panics in xhci_find_next_ext_cap()
>>> ( drivers/usb/host/xhci-ext-caps.h:122 )
>>> http://lxr.free-electrons.com/source/drivers/usb/host/xhci-ext-caps.h?v=4.9#L122
>>>
>>> Any idea how this can happen?
>>>
>>> 	base = ioremap_nocache(pci_resource_start(pdev, 0), len);
>>>
>>> Could I be passing garbage to ioremap_nocache?
>>
>> Oh...
>>
>> I have just now understood what Ard wrote a few days ago.
>>
>> The issue was that, on this platform, the PCI configuration space
>> and memory space are multiplexed; in other words they reside at
>> the same physical address, with a bit in MMIO to choose one or
>> the other.
> 
> Time to shoot another hardware engineer.

He's in CC :-)

> Hopefully it isn't an SMP system - but I wouldn't put it past them.

This is a dual- and quad- Cortex A9 MP platform :-(

Regards.