[openib-general] ib_mad shutdown WC status code ?

[Dror Goldenberg]

completing the list...

-----Original Message-----
From: Dror Goldenberg [mailto:gdror at mellanox.co.il] 
Sent: Sunday, September 26, 2004 8:17 PM
To: Sean Hefty; Fab Tillier
Cc: openib-general at openib.org
Subject: RE: [openib-general] ib_mad shutdown WC status code ?





> -----Original Message----- 
> From: Sean Hefty [mailto:mshefty at ichips.intel.com
<mailto:mshefty at ichips.intel.com> ] 
> Sent: Friday, September 24, 2004 6:41 PM 

> I think that flushed makes sense.  With queuing in the access 
> layer, we should be able to stop and restart the QP in most 
> error cases without affecting the user.  If the link goes 
> down, flushing the requests seems reasonable.  What other 
> cases would cause the MAD layer to shut down? 
> 

If link goes down, UD QP will go on "sending" the packets as 
if link was up all the time. You wouldn't get flushed WQEs in this 
case for a UD QP.  Receive queue is unaffected by the link
going down. 
In general, for UD QPs, you'll get flushed WQEs when the QP 
moves to the error state and that seldom happens. The exact 
scenarios for this to happen (hopefully I don't miss anything): 
- s/g element points at a wrong address/protection error 
- HCA can't fetch a WQE (e.g. bus error)  
- manually move the QP to the error state (modify QP) 

-Dror 

> - Sean 

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