Re: AW: AW: AW: [PATCH net] net: usb: lan78xx: restore VLAN filter table after device reset

[Nicolai Buchwitz]

Hi Sven

On 19.6.2026 15:31, Sven Schuchmann wrote:
> Hello Nicolai,
>
> looks good from my point of view
> (Calling the lan78xx_write_vlan_table() from
> lan78xx_mac_link_up() and from lan78xx_reset()).

Thanks.

> But I investigated a little more and it seems the hash table
> (which is right behind the vlan table in the controllers memory)
> also gets cleared. I wrote some random data into this table and have
> seen that it gets also cleared. I think this needs to be fixed too.

Something like

static int lan78xx_write_mchash_table(struct lan78xx_net *dev)
{
       struct lan78xx_priv *pdata = (struct lan78xx_priv 
*)(dev->data[0]);

       return lan78xx_dataport_write(dev, DP_SEL_RSEL_VLAN_DA_,
                                     DP_SEL_VHF_VLAN_LEN,
                                     DP_SEL_VHF_HASH_LEN, 
pdata->mchash_table); // from lan78xx_deferred_multicast_write)
}

with callers in lan78xx_deferred_multicast_write() and 
lan78xx_mac_link_up(), should
do the trick?

> In the Datasheet from the LAN7801 I can read:
> "After a reset event, the RFE will automatically initialize the 
> contents of the VHF to 0h."
> Where VHF also refers to the hash table.
> But I still do not understand what reset is happening when I just 
> unplug the network cable....

I suspect it is triggered from the PHY:

8.10 (MAC Reset Watchdog Timer):
"A portion of the MAC operates on clocks generated by the Ethernet PHY 
[...] PHY Reset
(PHY_RST) results in resetting the portion of the MAC operating on the 
PHY receive and
transmit clocks."

So which PHY are you using?

> [...]

Thanks,
Nicolai