Re: [PATCH net-next 5/5] net: dsa: b53: mark as non-legacy

[Florian Fainelli <f.fainelli@gmail.com>]

Hi Russell,

On 2/22/22 02:16, Russell King (Oracle) wrote:
> The B53 driver does not make use of the speed, duplex, pause or
> advertisement in its phylink_mac_config() implementation, so it can be
> marked as a non-legacy driver.
> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---
>   drivers/net/dsa/b53/b53_common.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
> index 50a372dc32ae..83bf30349c26 100644
> --- a/drivers/net/dsa/b53/b53_common.c
> +++ b/drivers/net/dsa/b53/b53_common.c
> @@ -1346,6 +1346,12 @@ static void b53_phylink_get_caps(struct dsa_switch *ds, int port,
>   	/* Get the implementation specific capabilities */
>   	if (dev->ops->phylink_get_caps)
>   		dev->ops->phylink_get_caps(dev, port, config);
> +
> +	/* This driver does not make use of the speed, duplex, pause or the
> +	 * advertisement in its mac_config, so it is safe to mark this driver
> +	 * as non-legacy.
> +	 */
> +	config->legacy_pre_march2020 = false;

This patch appears to cause a regression for me, I am not sure why I did 
not notice it back when I tested it but I suspect it had to do with me 
testing only with a copper module and not with a fiber module.

Now that I tested it again, the SFP port (port 5 in my set-up) link up 
interrupt does not fire up when setting config->legacy_pre_march2020 to 
false.

Here is a working log with phylink debugging enabled:

# udhcpc -i sfp
udhcpc: started, v1.35.0
[   49.479637] bgmac-enet 18024000.ethernet eth2: Link is Up - 
1Gbps/Full - flow control off
[   49.488139] Generic PHY fixed-0:02: PHY state change UP -> RUNNING
[   49.488256] b53-srab-switch 18036000.ethernet-switch sfp: configuring 
for inband/1000base-x link mode
[   49.504062] b53-srab-switch 18036000.ethernet-switch sfp: major 
config 1000base-x
[   49.511800] b53-srab-switch 18036000.ethernet-switch sfp: 
phylink_mac_config: mode=inband/1000base-x/Unknown/Unknown 
adv=0000000,00000201
[   49.527504] b53-srab-switch 18036000.ethernet-switch sfp: mac link down
[   49.535044] sfp sfp: SM: enter present:down:down event dev_up
[   49.541006] sfp sfp: tx disable 1 -> 0
[   49.544897] sfp sfp: SM: exit present:up:wait
[   49.549509] IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
udhcpc: broadcasting discover
[   49.595185] sfp sfp: SM: enter present:up:wait event timeout
[   49.601064] sfp sfp: SM: exit present:up:link_up
[   52.388917] b53-srab-switch 18036000.ethernet-switch sfp: mac link up
[   52.396513] b53-srab-switch 18036000.ethernet-switch sfp: Link is Up 
- 1Gbps/Full - flow control rx/tx
[   52.406145] IPv6: ADDRCONF(NETDEV_CHANGE): sfp: link becomes ready
udhcpc: broadcasting discover
udhcpc: broadcasting select for 192.168.3.156, server 192.168.3.1
udhcpc: lease of 192.168.3.156 obtained from 192.168.3.1, lease time 600
deleting routers
adding dns 192.168.1.1

and one that is not working with phylink debugging enabled:

# udhcpc -i sfp
udhcpc: started, v1.35.0
[   27.863529] bgmac-enet 18024000.ethernet eth2: Link is Up - 
1Gbps/Full - flow control off
[   27.872021] Generic PHY fixed-0:02: PHY state change UP -> RUNNING
[   27.872120] b53-srab-switch 18036000.ethernet-switch sfp: configuring 
for inband/1000base-x link mode
[   27.887952] b53-srab-switch 18036000.ethernet-switch sfp: major 
config 1000base-x
[   27.895689] b53-srab-switch 18036000.ethernet-switch sfp: 
phylink_mac_config: mode=inband/1000base-x/Unknown/Unknown 
adv=0000000,00000201
[   27.895802] b53-srab-switch 18036000.ethernet-switch sfp: mac link down
[   27.911945] sfp sfp: SM: enter present:down:down event dev_up
[   27.923947] sfp sfp: tx disable 1 -> 0
[   27.927835] sfp sfp: SM: exit present:up:wait
[   27.932442] IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
udhcpc: broadcasting discover
[   27.978181] sfp sfp: SM: enter present:up:wait event timeout
[   27.984056] sfp sfp: SM: exit present:up:link_up
[   30.686440] b53-srab-switch 18036000.ethernet-switch sfp: mac link up
udhcpc: broadcasting discover
udhcpc: broadcasting discover

The mac side appears to be UP but not no carrier is set to the sfp 
network device. Do you have any idea why that would happen?
-- 
Florian