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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 6 Jun 2023 11:30:47 +0200
Message-ID: <CAMuHMdXnMd=b1q+hmv1GsrugG7PhHXLznV5A0UKmoezaQY4oog@mail.gmail.com>
Subject: Re: [PATCH] net: stmmac: Fix build without PCS_LYNX
To:     Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc:     Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Simon Horman <simon.horman@corigine.com>,
        netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org,
        linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Geert Uytterhoeven <geert+renesas@glider.be>
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On Tue, Jun 6, 2023 at 10:27 AM Geert Uytterhoeven
<geert+renesas@glider.be> wrote:
> If STMMAC_ETH=y, but PCS_LYNX=n (e.g. shmobile_defconfig):
>
>     arm-linux-gnueabihf-ld: drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.o: in function `stmmac_mdio_unregister':
>     stmmac_mdio.c:(.text+0xfbc): undefined reference to `lynx_pcs_destroy'
>
> As pcs_lynx is used only on dwmac_socfpga, fix this by adding a check
> for PCS_LYNX to the cleanup path in the generic driver.
>
> Fixes: 5d1f3fe7d2d54d04 ("net: stmmac: dwmac-sogfpga: use the lynx pcs driver")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> index c784a6731f08e108..53ed59d732210814 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> @@ -665,7 +665,7 @@ int stmmac_mdio_unregister(struct net_device *ndev)
>         if (priv->hw->xpcs)
>                 xpcs_destroy(priv->hw->xpcs);
>
> -       if (priv->hw->lynx_pcs)
> +       if (IS_ENABLED(CONFIG_PCS_LYNX) && priv->hw->lynx_pcs)
>                 lynx_pcs_destroy(priv->hw->lynx_pcs);
>
>         mdiobus_unregister(priv->mii);

As pointed out by Arnd, this doesn't work when PCS_LYNX is a loadable
module and STMMAC is built-in:
https://lore.kernel.org/r/11bd37e9-c62e-46ba-9456-8e3b353df28f@app.fastmail.com

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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