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Subject: Re: PCIE device errors after linux kernel upgrade
From: Scott Wood <scottwood@freescale.com>
To: ravich <lravich@gmail.com>
Date: Wed, 8 Jan 2014 15:07:31 -0600
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On Wed, 2014-01-08 at 00:24 -0800, ravich wrote:
> Finally I found the problem causing the sudden system reset :
> 
> our setup :
> 
> P2020<====>PCI Bridge <=====> FPGA
> 
> The reset occurs when we allocating skb and giving the Fpga dma addr of
> skb->data of this skb and when the FPGA tries to reach this address we are
> having a hardware reset. 
> 
> To fixed it we used GFP_DMA flag on skb allocations.
> 
> If you can explain me few thinks I will be more  then happy :
> 1) how come we managed to work in 2.6.32 kernel without this flag.

Maybe you got lucky, allocation patterns changed, etc?

> 2) Ok gave you a bad dma address why reset the system without  any warning. 

If you write to random addresses arbitrary things can happen.

-Scott