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Date:   Mon, 24 Oct 2022 21:30:57 +0100
From:   Matthew Garrett <mjg59@srcf.ucam.org>
To:     Hans de Goede <hdegoede@redhat.com>
Cc:     Dmitry Osipenko <digetx@gmail.com>,
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Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another
 backlight should be used (v2)
Message-ID: <20221024203057.GA28675@srcf.ucam.org>
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On Tue, Sep 27, 2022 at 01:04:52PM +0200, Hans de Goede wrote:

> So to fix this we need to make acpi_video_get_backlight_type()
> return native on the Acer Chromebook Spin 713.

Isn't the issue broader than that? Unless the platform is Windows 8 or 
later, we'll *always* (outside of some corner cases) return 
acpi_backlight_vendor if there's no ACPI video interface. This is broken 
for any platform that implements ACPI but relies on native video 
control, which is going to include a range of Coreboot platforms, not 
just Chromebooks. I think for this to work correctly you need to have 
the infrastructure be aware of whether or not a vendor interface exists, 
which means having to handle cleanup if a vendor-specific module gets 
loaded later.