On 07/02/2017 01:37 PM, Geert Uytterhoeven wrote: > 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. It sure does fix a real issue, but I am really concerned about the inability to test this patch in a configuration where we have multiple PHY(s) or MDIO device(s) hanging off the same MDIO bus and one of those requesting an EPROBE_DEFER. I currently don't have a setup where I could exercise this, Andrew, do you? -- Florian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
