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Subject: Re: [PATCH] powerpc/pseries: Avoid context switch in EEH reset if
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From: Benjamin Herrenschmidt <benh@au1.ibm.com>
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Date: Wed, 28 Jan 2015 10:58:42 +1100
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Cc: linuxppc-dev@lists.ozlabs.org, wenxiong@linux.vnet.ibm.com,
 Gavin Shan <gwshan@linux.vnet.ibm.com>, Brian J King <bjking1@us.ibm.com>
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On Tue, 2015-01-27 at 16:58 -0600, Brian King wrote:
> I'd argue we are our own worst enemy here really. The new user is EEH
> code.
> I don't see a huge reason that code would need to use this exact same
> API.
> 
> > In fact, even with IPR and the existing call, how do you wait for
> the link to come
> > back for a PERST ? That can take a while...
> 
> Basically, I assert reset, delay for 1/2 second via a timer interrupt,
> deassert reset,
> delay for 2 seconds via another timer interrupt, then proceed with
> adapter initialization.

I'm surprised that even works properly... for example in the case of
PERST we need to mask various error traps before asserting and unmask
them when the link comes up (such as the surprise link down error), I
don't see an opportunity in that scheme for FW to do that latter...

Ben.