On Tue, Jun 6, 2017 at 11:43 AM, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > On Tue, May 23, 2017 at 11:36 AM, Geert Uytterhoeven > <geert@xxxxxxxxxxxxxx> wrote: >> On Fri, May 19, 2017 at 12:21 AM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote: >>> On 05/18/2017 01:36 PM, Geert Uytterhoeven wrote: >>>> On Thu, May 18, 2017 at 9:34 PM, Andrew Lunn <andrew@xxxxxxx> wrote: >>>>>>> This most certainly works fine in the simple case where you have one PHY >>>>>>> hanging off the MDIO bus, now what happens if you have several? >>>>>>> >>>>>>> Presumably, the first PHY that returns EPROBE_DEFER will make the entire >>>>>>> bus registration return EPROB_DEFER as well, and so on, and so forth, >>>>>>> but I am not sure if we will be properly unwinding the successful >>>>>>> registration of PHYs that either don't have an interrupt, or did not >>>>>>> return EPROBE_DEFER. >>>>>>> >>>>>>> It should be possible to mimic this behavior by using the fixed PHY, and >>>>>>> possibly the dsa_loop.c driver which would create 4 ports, expecting 4 >>>>>>> fixed PHYs to be present. >>>>>> >>>>>> mdiobus_unregister(), called from of_mdiobus_register() on failure, >>>>>> should do the unwinding, right? >>>>>> >>>>>> And when the driver is reprobed, all PHYs are reprobed, until they all >>>>>> succeed. >>>>> >>>>> That is the theory. I looked at that while reviewing the patch. But >>>>> this has probably not been tested in anger. It would be good to test >>>>> this properly, with not just the first PHY returning -EPROBE_DEFER, to >>>>> really test the unwind. >>>> >>>> Unfortunately I don't have a board with multiple PHYs, so I cannot test >>>> that case. >> >> I tried adding a few dummy PHYs in DT, but that didn't work. >> >> So how can we proceed? >> >> I think the only way my patch can cause issues is because some systems >> may rely on EPROBE_DEFER errors being ignored. >> >>>> Does unbinding/rebinding a network driver with multiple PHYs currently >>>> work? Or module unload/reload? >>> >>> Usually there is a strict 1:1 mapping between a network device (not >>> driver) and a PHY device, switch drivers however, would have multiple >>> PHYs (one per port, aka net_deice). >>> >>> NB: binding and unbinding of PHYs is pretty broken at the moment though, >>> because there is a complete disconnect between what the Ethernet MAC >>> expects, and the state in which the PHY is. I had some patches to fix >>> that, but this turned out to be playing whack-a-mole which I typically >>> suck at. >> >> I didn't mean unbinding the PHY, but the network device. >> Don't you have the same issue with the state of PHYs as left by the bootloader? > > Anyone who can test the behavior on an Ethernet device with multiple PHYs, > e.g. by faking an -EPROBE_DEFER somewhere in the middle? > > I'd like to get this issue fixed in v4.13, to avoid a regression when migrating > several systems to a new and better clock driver in v4.14, which will trigger > EPROBE_DEFER. Ping? This patch fixes a real issue. Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds