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:

quoted

quoted

-----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 <redacted>

Acked-by: Shaopeng He <redacted>

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.

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"?

/Bruce