From:   Kalle Valo <kvalo@kernel.org>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Stanislaw Gruszka <stf_xl@wp.pl>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Luca Coelho <luciano.coelho@intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
        Ayala Beker <ayala.beker@intel.com>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] iwlwifi: fix LED dependencies
References: <20211204173848.873293-1-arnd@kernel.org>
Date:   Tue, 07 Dec 2021 09:04:56 +0200
In-Reply-To: <20211204173848.873293-1-arnd@kernel.org> (Arnd Bergmann's
        message of "Sat, 4 Dec 2021 18:38:33 +0100")
Message-ID: <87ilw0uc87.fsf@codeaurora.org>
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Arnd Bergmann <arnd@kernel.org> writes:

> From: Arnd Bergmann <arnd@arndb.de>
>
> The dependencies for LED configuration are highly inconsistent and too
> complicated at the moment. One of the results is a randconfig failure I
> get very rarely when LEDS_CLASS is in a loadable module, but the wireless
> core is built-in:
>
> WARNING: unmet direct dependencies detected for MAC80211_LEDS
>   Depends on [n]: NET [=y] && WIRELESS [=y] && MAC80211 [=y] && (LEDS_CLASS [=m]=y || LEDS_CLASS [=m]=MAC80211 [=y])
>   Selected by [m]:
>   - IWLEGACY [=m] && NETDEVICES [=y] && WLAN [=y] && WLAN_VENDOR_INTEL [=y]
>   - IWLWIFI_LEDS [=y] && NETDEVICES [=y] && WLAN [=y] && WLAN_VENDOR_INTEL [=y] && IWLWIFI [=m] && (LEDS_CLASS [=m]=y || LEDS_CLASS [=m]=IWLWIFI [=m]) && (IWLMVM [=m] || IWLDVM [=m])
>
> aarch64-linux-ld: drivers/net/wireless/ath/ath5k/led.o: in function `ath5k_register_led':
> led.c:(.text+0x60): undefined reference to `led_classdev_register_ext'
> aarch64-linux-ld: drivers/net/wireless/ath/ath5k/led.o: in function `ath5k_unregister_leds':
> led.c:(.text+0x200): undefined reference to `led_classdev_unregister'
>
> For iwlwifi, the dependency is wrong, since this config prevents the
> MAC80211_LEDS code from being part of a built-in MAC80211 driver.
>
> For iwlegacy, this is worse because the driver tries to force-enable
> the other subsystems, which is both a layering violation and a bug
> because it will still fail with MAC80211=y and IWLEGACY=m, leading
> to LEDS_CLASS being a module as well.
>
> The actual link failure in the ath5k driver is a result of MAC80211_LEDS
> being enabled but not usable. With the Kconfig logic fixed in the
> Intel drivers, the ath5k driver works as expected again.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Luca, I would like to take this to wireless-drivers. Ack?

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