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From:   AceLan Kao <acelan.kao@canonical.com>
Date:   Wed, 7 Jun 2023 14:13:31 +0800
Message-ID: <CAFv23QkEdGnEz1q7vbyFCa9S9Dqh-zec72nRGyZ3wAz-8wpbvA@mail.gmail.com>
Subject: Re: [PATCH] platform/x86: dell-laptop: Add drm module soft dependency
To:     Matthew Garrett <mjg59@srcf.ucam.org>
Cc:     =?UTF-8?Q?Pali_Roh=C3=A1r?= <pali@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Mark Gross <markgross@kernel.org>,
        platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kai-Heng Feng <kai.heng.feng@canonical.com>
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Matthew Garrett <mjg59@srcf.ucam.org> =E6=96=BC 2023=E5=B9=B46=E6=9C=887=E6=
=97=A5 =E9=80=B1=E4=B8=89 =E4=B8=8B=E5=8D=881:27=E5=AF=AB=E9=81=93=EF=BC=9A
>
> On Wed, Jun 07, 2023 at 01:19:40PM +0800, AceLan Kao wrote:
> > Gfx drivers(i915/amdgpu/nvidia) depend on the drm driver, so delaying
> > the loading of dell_laptop after drm can ease the issue the most.
> > Right, it's still possible to encounter the issue, unfortunately, we
> > do not have a better solution for it at the moment.
>
> We could unregister inappropriate backlight drivers when a more
> appropriate one is loaded, or the policy decision around which driver to
> use could be made in userland?
It's hard to decide which backlight driver is redundant, and it's kind of u=
gly
to unregister the backlight driver which is registered by other driver and =
maybe
problematic.

I'm not familiar with userland, but I think we should handle this
issue within the
kernel and aim to register only one functional backlight driver.