Re: [Xen-devel] VT-d flush timeout

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Dong, Eddie wrote on 2014-09-26:
>>>> 
>>> 
>>> Giving this path of long time wait-loop only happens at the case
>>> when the hardware fails, I don't care if it enters panic in 1
>>> seconds or in 10ms seconds. But the software compatibility (for
>>> all existing platforms and potential future platforms) is much more 
>>> important.
>> 
>> I agree for the paths leading to a panic(). But there's one such
>> case where it
>> doesn't: snb_vtd_ops_preamble().
>> 
> 
> For some reason, it is using a same MAGIC TIMEOUT value with VTd flush
> timeout. They are actually different and this one is used to prevent the
> IGD to enter RC6 state :)
> 
> Whether the IGD enters RC6 state in 1second is another story, it
> doesn't indicate the hardware is bad, like the VTD flush timeout
> indicates. So it is not necessary to enter panic.
> 
> Maybe we should cook a patch to use different TIMEOUT MACRO, though
> they are 1second in both cases.

Agree. It's better to use another MACRO since it totally has nothing to do with 
VT-D.

> 
> Thx Eddie


Best regards,
Yang



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