Re: Issues with smsc95xx driver since a049a30fc27c

On 2021-12-18 18:45, Andrew Lunn wrote:

On Fri, Dec 17, 2021 at 03:45:08PM +0000, Martyn Welch wrote:

quoted

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 [off-list ref]
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

hi Andrew,

on my odroid-u3, with all kernel versions since 5.15.6 (where the patch was applied) and also with 5.16.y if tcpdump is running the network works. when tcpdump process is killed/stopped, networking stops working.

1. as a test that this is the offending patch, i've recompiled the fedora kernel 5.15.7 with the patch reverted and everything was working normally as it last worked with 5.15.5

2.1. kernel 5.15.5 - "mii-tool -vvv eth0"

Using SIOCGMIIPHY=0x8947
eth0: negotiated 1000baseT-HD flow-control, link ok
  registers for MII PHY 1:
    3100 782d 0007 c101 01e1 45e1 0001 ffff
    ffff ffff ffff ffff ffff 0000 0000 0000
    0040 0002 00e1 ffff 0000 0000 0000 0000
    0b9d 0000 0000 000a 0000 00c8 0000 1058
  product info: vendor 00:01:f0, model 16 rev 1
  basic mode:   autonegotiation enabled
  basic status: autonegotiation complete, link ok
  capabilities: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  advertising:  1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  link partner: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control

2.2. kernel 5.15.8 - "mii-tool -vvv eth0"

Using SIOCGMIIPHY=0x8947
eth0: negotiated 1000baseT-HD flow-control, link ok
  registers for MII PHY 1:
    3100 782d 0007 c101 01e1 45e1 0003 ffff
    ffff ffff ffff ffff ffff 0000 0000 0000
    0040 0002 00e1 ffff 0000 0000 0000 0000
    0b9d 0000 0000 000a 0000 00c8 0000 1058
  product info: vendor 00:01:f0, model 16 rev 1
  basic mode:   autonegotiation enabled
  basic status: autonegotiation complete, link ok
  capabilities: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  advertising:  1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  link partner: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control

3.1 kernel 5.15.5 - "dmesg | grep -i phy"

[    0.000000] Booting Linux on physical CPU 0xa00
[    0.000000] GIC physical location is 0x10490000
[    2.290065] libphy: Fixed MDIO Bus: probed
[    6.763235] samsung-usb2-phy 125b0000.exynos-usbphy: supply vbus not found, using dummy regulator
[    8.045968] libphy: smsc95xx-mdiobus: probed
[   23.261816] Generic PHY usb-001:002:01: attached PHY driver (mii_bus:phy_addr=usb-001:002:01, irq=POLL)

3.1 kernel 5.15.8 - "dmesg | grep -i phy"

[    0.000000] Booting Linux on physical CPU 0xa00
[    0.000000] GIC physical location is 0x10490000
[    3.291292] libphy: Fixed MDIO Bus: probed
[   10.198145] samsung-usb2-phy 125b0000.exynos-usbphy: supply vbus not found, using dummy regulator
[   11.740943] libphy: smsc95xx-mdiobus: probed
[   11.742916] Generic PHY usb-001:002:01: attached PHY driver (mii_bus:phy_addr=usb-001:002:01, irq=POLL)