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From:   Arnd Bergmann <arnd@kernel.org>
Date:   Sat, 24 Jul 2021 08:55:31 +0200
Message-ID: <CAK8P3a3u_jsxQW4dPXtsdKkw1mjKXL-h=qN1SGHytvUMPf3fPw@mail.gmail.com>
Subject: Re: [PATCH] nouveau: make backlight support non optional
To:     Karol Herbst <kherbst@redhat.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Lyude Paul <lyude@redhat.com>, Ben Skeggs <bskeggs@redhat.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        ML nouveau <nouveau@lists.freedesktop.org>,
        dri-devel <dri-devel@lists.freedesktop.org>
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On Sat, Jul 24, 2021 at 12:47 AM Karol Herbst <kherbst@redhat.com> wrote:
>
> In the past this only led to compilation issues. Also the small amount of
> extra .text shouldn't really matter compared to the entire nouveau driver
> anyway.
>

>         select DRM_TTM_HELPER
> -       select BACKLIGHT_CLASS_DEVICE if DRM_NOUVEAU_BACKLIGHT
> -       select ACPI_VIDEO if ACPI && X86 && BACKLIGHT_CLASS_DEVICE && INPUT
> +       select BACKLIGHT_CLASS_DEVICE
> +       select ACPI_VIDEO if ACPI && X86 && INPUT
>         select X86_PLATFORM_DEVICES if ACPI && X86
>         select ACPI_WMI if ACPI && X86

I think the logic needs to be the reverse: instead of 'select
BACKLIGHT_CLASS_DEVICE',
this should be 'depends on BACKLIGHT_CLASS_DEVICE', and the same for ACPI_VIDEO.

We may want to add 'default DRM || FB' to BACKLIGHT_CLASS_DEVICE in the
process so we don't lose it for users doing 'make oldconfig' or 'make defconfig'

The rest of the patch looks good to me.

       Arnd