31st address line sometimes not used on EHCI/UHCI/OHCI

[Julian Elischer]

Hans Petter Selasky wrote:
> On Sunday 27 May 2007 23:53, John-Mark Gurney wrote:
>> Hans Petter Selasky wrote this message on Sun, May 27, 2007 at 22:35 +0200:
>>> I've got some reports back that some USB host controllers do not support
>>> transferring memory from a location higher than 2GB.
>>>
>>> What should we do about this?
>>>
>>> Should we limit all USB DMA allocations to the lower 2GB of the memory?
>> No, a quirk table should be setup and pass the restriction to bus_dma
>> at tag initalization time when a broken controller is detected..
> 
> Yes, I can do that. But I am also thinking about a static quirk, like a sysctl 
> you can set at boot time.
> 
> I hope that this is not a wide-spread problem.

What manufacturers are we talking about here? and is there any possibility that
it's not the USB chipset, but rather, some feature of an intermediary bus?

> 
> And I am not surprised that hardware manufacturers are not specification 
> compliant, which really makes me wonder if they support a true 64-bit address 
> bus on the EHCI controller at all. I would maybe cost too much money? And 
> therefore we should just stick with 32-bit addressing on 32-bit platforms 
> aswell.
> 
> --HPS
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