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Old 09-19-12, 02:32 PM   #9
Godlikearg
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Join Date: Jan 2009
Posts: 12
Default Re: K1000M on Thinkpad W530: card falls off the bus

One more thing: after doing more testing at the request of the Bumblebee guys, I could see that IOMMU kernel configuration has an impact too. Without this option compiled in:

Code:
CONFIG_CALGARY_IOMMU:                                       
                                                            
Support for hardware IOMMUs in IBM's xSeries x366 and x460  
systems. Needed to run systems with more than 3GB of memory 
properly with 32-bit PCI devices that do not support DAC    
(Double Address Cycle). Calgary also supports bus level     
isolation, where all DMAs pass through the IOMMU.  This     
prevents them from going anywhere except their intended     
destination. This catches hard-to-find kernel bugs and      
mis-behaving drivers and devices that do not use the DMA-API
properly to set up their DMA buffers.  The IOMMU can be     
turned off at boot time with the iommu=off parameter.       
Normally the kernel will make the right choice by itself.   
If unsure, say Y.
while I would not get "has fallen off the bus" I do get the following messages (rminitcontext etc) and the card is unusable.
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