Re: [dpdk-dev] [PATCH v2] ixgbe: fix link down issue on x550em_x

["Lu, Wenzhuo" <wenzhuo.lu@intel.com>]

Hi Bruce,


> -----Original Message-----
> From: Richardson, Bruce
> Sent: Thursday, February 25, 2016 9:30 PM
> To: Lu, Wenzhuo
> Cc: He, Shaopeng; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2] ixgbe: fix link down issue on x550em_x
> 
> On Thu, Feb 25, 2016 at 01:32:33AM +0000, Lu, Wenzhuo wrote:
> > Hi Bruce,
> >
> > > -----Original Message-----
> > > From: Richardson, Bruce
> > > Sent: Wednesday, February 24, 2016 10:26 PM
> > > To: He, Shaopeng
> > > Cc: Lu, Wenzhuo; dev@dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH v2] ixgbe: fix link down issue on
> > > x550em_x
> > >
> > > On Thu, Feb 04, 2016 at 06:21:04AM +0000, He, Shaopeng wrote:
> > > >
> > > > > -----Original Message-----
> > > > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wenzhuo Lu
> > > > > Sent: Monday, February 01, 2016 4:43 PM
> > > > > To: dev@dpdk.org
> > > > > Subject: [dpdk-dev] [PATCH v2] ixgbe: fix link down issue on
> > > > > x550em_x
> > > > >
> > > > > Normally the auto-negotiation is supported by FW. But on
> > > > > X550EM_X_10G_T it's not supported by FW. As the port of
> > > > > X550EM_X_10G_T is 10G. If we connect the port with a peer which
> > > > > is 1G. The link is always down.
> > > > > We have to supprted auto-neg by SW to avoid such link down issue.
> > > > >
> > > > > Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
> > > > Acked-by: Shaopeng He <shaopeng.he@intel.com>
> > > >
> > > I'm a bit confused regarding the commit message and the code in the patch.
> > > The commit message talks about enabling speed auto-negotiation,
> > > while the code never refers to any such thing. Instead all we have
> > > are settings for manipulating interrupt masks to enable PHY
> > > interrupts. I think some additional information is needed to connect A and B
> together here.
> > The reason is that the handler of the link speed auto-neg is already in the base
> code. It's ixgbe_handle_lasi.
> > What we need is a trigger. When the advertised link speed changes, a PHY
> interruption will be triggered. So, we should handle this interruption and call
> ixgbe_handle_lasi to set the link speed correct.
> > Let me add more explanation in the commit log.
> >
> Yes, please do. What you have just explained makes much more sense and
> should be included in the log.
> 
> > >
> > > A second, more minor nit is that the commit title never refers to
> > > link auto- negotiation, but refers to this as a bug fix - which is
> > > also correct. If this is primarily a bug fix, please include a fixes
> > > line if possible, but please also refer to auto-neg in the title if possible too.
> > I didn't add a fixes line because it doesn't fix an issue introduced by SW, or
> even FW, HW. As said in commit log, we hit a link down issue, but the root cause
> is the link speed auto-neg is not supported on this specific NIC.
> > On the other NICs, link speed auto-neg is supported by FW, SW need no do
> anything. So we didn't implement the link speed auto-neg. But we have to
> implement this feature on this NIC for FW doesn't implement it.
> > Should I change the tittle to "support link speed auto-neg on x550em_x"?
> >
> 
> Yes, that is probably better.
Thanks for the comments. I'll send a new version.

> 
> Thanks,
> /Bruce