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From:   Benjamin Gaignard <benjamin.gaignard@linaro.org>
Date:   Thu, 5 Apr 2018 13:05:05 +0200
Message-ID: <CA+M3ks4RPe_jo-LKKCNU22fzQWO3nvJEiZYg_mB6tSVd9PgqZA@mail.gmail.com>
Subject: Re: [PATCH] drm/sti: Depend on OF rather than selecting it
To:     "Oliver O'Halloran" <oohall@gmail.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Vincent Abriou <vincent.abriou@st.com>,
        David Airlie <airlied@linux.ie>,
        dri-devel@lists.freedesktop.org, linux-ia64@vger.kernel.org,
        stable@vger.kernel.org
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2018-04-03 7:34 GMT+02:00 Oliver O'Halloran <oohall@gmail.com>:
> Commit cc6b741c6f63 ("drm: sti: remove useless fields from vtg
> structure") reworked some code inside of this driver and made it select
> CONFIG_OF. This results in the entire OF layer being enabled when
> building an allmodconfig on ia64. OF on ia64 is completely unsupported
> so this isn't a great state of affairs.
>
> The 0day robot noticed a link-time failure on ia64 caused by
> using of_node_to_nid() in an otherwise unrelated driver. The
> generic fallback for of_node_to_nid() only exists when:
>
>         defined(CONFIG_OF) && defined(CONFIG_NUMA) == false
>
> Since CONFIG_NUMA is usually selected for IA64 we get the link failure.
> Fix this by making the driver depend on OF rather than selecting it,
> odds are that was the original intent.
>
> Link: https://lists.01.org/pipermail/kbuild-all/2018-March/045172.html
> Fixes: cc6b741c6f63 ("drm: sti: remove useless fields from vtg structure")
> Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
> Cc: Vincent Abriou <vincent.abriou@st.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-ia64@vger.kernel.org
> Cc: stable@vger.kernel.org
> Signed-off-by: Oliver O'Halloran <oohall@gmail.com>

Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>

> ---
> Cc`ed to stable since the ia64 guys might want it backported. I'm not
> bothered if it just goes into mainline.
> ---
>  drivers/gpu/drm/sti/Kconfig | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/sti/Kconfig b/drivers/gpu/drm/sti/Kconfig
> index cca4b3c9aeb5..1963cc1b1cc5 100644
> --- a/drivers/gpu/drm/sti/Kconfig
> +++ b/drivers/gpu/drm/sti/Kconfig
> @@ -1,6 +1,6 @@
>  config DRM_STI
>         tristate "DRM Support for STMicroelectronics SoC stiH4xx Series"
> -       depends on DRM && (ARCH_STI || ARCH_MULTIPLATFORM)
> +       depends on OF && DRM && (ARCH_STI || ARCH_MULTIPLATFORM)
>         select RESET_CONTROLLER
>         select DRM_KMS_HELPER
>         select DRM_GEM_CMA_HELPER
> @@ -8,6 +8,5 @@ config DRM_STI
>         select DRM_PANEL
>         select FW_LOADER
>         select SND_SOC_HDMI_CODEC if SND_SOC
> -       select OF
>         help
>           Choose this option to enable DRM on STM stiH4xx chipset
> --
> 2.9.5
>