Messages in this thread | | | From | Vladimir Oltean <> | Date | Tue, 21 Apr 2020 14:56:37 +0300 | Subject | Re: dsa: sja1105: regression after patch: "net: dsa: configure the MTU for switch ports" |
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Hi Oleksij,
On Tue, 21 Apr 2020 at 14:33, Oleksij Rempel <o.rempel@pengutronix.de> wrote: > > Hi Vladimir, > > I have a regression after this patch: > |commit bfcb813203e619a8960a819bf533ad2a108d8105 > |Author: Vladimir Oltean <vladimir.oltean@nxp.com> > | > | net: dsa: configure the MTU for switch ports > > with following log: > [ 3.044065] sja1105 spi1.0: Probed switch chip: SJA1105Q > [ 3.071385] sja1105 spi1.0: Enabled switch tagging > [ 3.076484] sja1105 spi1.0: error -34 setting MTU on port 0 > [ 3.082795] sja1105: probe of spi1.0 failed with error -34 > > this is devicetree snippet for the port 0: > port@0 { > reg = <0>; > label = "usb"; > phy-handle = <&usbeth_phy>; > phy-mode = "rmii"; > }; > > > Is it know issue? > > Regards, > Oleksij > -- > Pengutronix e.K. | | > Steuerwalder Str. 21 | http://www.pengutronix.de/ | > 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
The code which is causing problems seems to be this one:
mtu_limit = min_t(int, master->max_mtu, dev->max_mtu); old_master_mtu = master->mtu; new_master_mtu = largest_mtu + cpu_dp->tag_ops->overhead; if (new_master_mtu > mtu_limit) return -ERANGE;
called from
rtnl_lock(); ret = dsa_slave_change_mtu(slave_dev, ETH_DATA_LEN); rtnl_unlock(); if (ret && ret != -EOPNOTSUPP) { dev_err(ds->dev, "error %d setting MTU on port %d\n", ret, port->index); goto out_free; }
Before this patch, it was silently failing, now it's preventing the probing of the ports which I might agree with you is not better. Andrew warned about this, and I guess that during probe, we should warn but ignore any nonzero return code, not just EOPNOTSUPP. I'll send a patch out shortly to correct this.
Out of curiosity, what DSA master port do you have? Does it not support an MTU of 1504 bytes? Does MTU-sized traffic pass correctly through your interface? (you can test with iperf3)
Thanks, -Vladimir
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