Messages in this thread | | | Date | Fri, 31 Aug 2018 17:08:38 +0200 | From | Antoine Tenart <> | Subject | Re: [PATCH net-next v3 02/10] net: mvpp2: phylink support |
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Hi Russell,
On Fri, Aug 31, 2018 at 03:11:23PM +0100, Russell King - ARM Linux wrote: > On Fri, Aug 31, 2018 at 03:36:51PM +0200, Antoine Tenart wrote: > > With the above code remove one case did not worked anymore: when the > > port is configured as a fixed-link because the SFP cage can't be > > described and used (on the 7040-db and 8040-db boards). In such cases > > phylink is called, mac_config() is called, but link_up() is never > > called. I'm not sure this is actually an issue in phylink, but the PPv2 > > driver should probably take care of this weird case itself (by calling > > explicitly link_up()). What do you think? > > Fixed link should work: > > - when a fixed link is configured, link_config.link is set true. > - when phylink_start() is called, mac_config() will be called to do the > initial setup, and a resolve is triggered. > - phylink_resolve() will read the fixed link state, which in the case > of no GPIO, will inherit link_config.link. > - you will then see another mac_config() call. > > Now what happens depends whether you've set the netdev's carrier state > in the driver - if you haven't, the netdev's carrier state should be > off. Since the state mismatches the link_state.link (which will be > true), you will get a mac_link_up() call.
OK, that makes sense. Thanks for the explanations.
> mvneta ensures this state by always calling netif_carrier_off() in > mvneta_open(), maybe that ought to be in phylink_start() as that's the > state that phylink expects when phylink_start() has been called. So, > maybe it's a phylink bug. > > Can you see any down-sides to moving the netif_carrier_off() in > mvneta_open() to phylink_start() ?
I removed most of my previous fix, and called netif_carrier_off() just before phylink_start() in PPv2. I worked, and it seemed to me all cases were working fine.
As calling netif_carrier_off() seems to be a phylink assumption, I would agree to call it directly from within phylink_start(). But I don't have the full picture here.
If such a solution is OK for you, and if no one raises an issue in the next days, I can send a series to add a netif_carrier_off() call, fix PPv2, and remove mvneta's call to netif_carrier_off() in mvneta_open().
Thanks! Antoine
-- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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