Subject: Re: thunderx sgmii interface hang

From: Andrew Lunn <[email-masked]>
Date: Fri, 22 Dec 2017 23:45:07 +0100

> Currently I'm not using the DP83867_PHY driver (after verifying the
> issue occurs with or without that driver).
> 
> It does not occur if I limit UDP (ie 950mbps). I disabled all offloads
> and the issue still occurs.

> I'm told that the particular Cavium reference board with an SGMII phy
> doesn't show this issue (I don't have that specific board to do my own
> testing or comparisons against our board) so I'm inclined to think it
> has something to do with an interaction with the DP83867 PHY. I would
> like to start poking at PHY registers to see if I can find anything
> unusual. The best way to do that from userspace is via
> SIOCGMIIREG/SIOCSMIIREG right? The thunderx nic doesn't currently
> support ioctl's so I guess I'll have to add that support unless
> there's a way to get at phy registers from userspace through a phy
> driver?

phy_mii_ioctl() does what you need, and is simple to use.

mii-tool will then give you access to the standard PHY registers.

	 Andre