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Date: Wed, 15 Apr 2015 08:57:31 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: "Zhou, Danny" <danny.zhou@intel.com>
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Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] UIO pci-generic support broke igb_uio
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On Wed, 15 Apr 2015 07:19:39 +0000
"Zhou, Danny" <danny.zhou@intel.com> wrote:

> Could you please send out the steps for us to reproduce it? I guess you have applied
> v6 interrupt patches to perform interrupt related tests, right?
> 
> We cannot reproduce it now.
> 
> The support to in_kernel uio_pci_generic avoids using igb_uio this DPDK specific kernel module, 
> so it will be much easier for any Linux distribution to package DPDK.


Very simple. Run with link state enabled and igb_uio driver.

Looking more closely, I think the right way to fix this is to fix the
upstream uio_pci_generic to support controlling interrupts properly, rather
than trying to do it directly in userspace.

The problem is that doing it userspace is inherently racy because
the userspace config access does not do proper locking.

It really is an upstream kernel bug. Will send patch upstream to do it
the right way. But that won't help distributions.