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Message-ID: <CAMuHMdWWfaP8=H7H+UzrmOYpydi2mGLFGzuk9FQWJtEOug6u5g@mail.gmail.com> Date: Tue, 23 May 2017 11:36:47 +0200 From: Geert Uytterhoeven <geert@...ux-m68k.org> To: Florian Fainelli <f.fainelli@...il.com> Cc: Andrew Lunn <andrew@...n.ch>, Geert Uytterhoeven <geert+renesas@...der.be>, Rob Herring <robh+dt@...nel.org>, Frank Rowand <frowand.list@...il.com>, Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>, Sergei Shtylyov <sergei.shtylyov@...entembedded.com>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, Linux-Renesas <linux-renesas-soc@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Hi Florian, On Fri, May 19, 2017 at 12:21 AM, Florian Fainelli <f.fainelli@...il.com> wrote: > On 05/18/2017 01:36 PM, Geert Uytterhoeven wrote: >> On Thu, May 18, 2017 at 9:34 PM, Andrew Lunn <andrew@...n.ch> 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? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org 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
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