Re: Issues with smsc95xx driver since a049a30fc27c

[Andrew Lunn <andrew@lunn.ch>]

On Fri, Dec 17, 2021 at 03:45:08PM +0000, Martyn Welch wrote:
> I've had some reports of the smsc95xx driver failing to work for the
> ODROID-X2 and ODROID-U3 since a049a30fc27c was merged (also backported
> to 5.15.y stable branch, which I believe is what those affected by this
> are using).
> 
> Since then we have performed a number of tests, here's what we've found
> so far:
> 
> ODROID-U3 (built-in LAN9730):
> 
>  - No errors reported from smsc95xx driver, however networking broken
>    (can not perform DHCP via NetworkManager, Fedora user space).
> 
>  - Networking starts working if device forced into promiscuous mode
>    (Gabriel noticed this whilst running tcpdump)
> 
> 
> ODROID-X2 (built in LAN9514):
> 
>  - Networking not brought up (Using Debian Buster and Bullseye with
> traditional `/etc/network/interfaces` approach).
> 
>  - As with Odroid-u3, works when running in promiscuous mode.

Hi Martyn

Promisc mode is really odd, given what

commit a049a30fc27c1cb2e12889bbdbd463dbf750103a
Author: Martyn Welch <martyn.welch@collabora.com>
Date:   Mon Nov 22 18:44:45 2021 +0000

    net: usb: Correct PHY handling of smsc95xx

does. Has it been confirmed this is really the patch which causes
the problem?

Does mii-tool -vvv how any difference between the working and broken
case?

Can you also confirm the same PHY driver is used before/after this
patch. There is a chance one is using a specific PHY driver and the
other genphy.

    Andrew