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From:   Karol Herbst <kherbst@redhat.com>
Date:   Fri, 19 Aug 2022 17:44:48 +0200
Message-ID: <CACO55tuw_2QWFMr0t6-JfUiQ4M7V3ZMKC7jHYTyERypaU3TekQ@mail.gmail.com>
Subject: Re: [RFC 0/2] Stop the abuse of Linux-* _OSI strings
To:     Mario Limonciello <mario.limonciello@amd.com>,
        Lyude Paul <lyude@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        rafael@kernel.org, Len Brown <lenb@kernel.org>,
        nouveau@lists.freedesktop.org, hdegoede@redhat.com,
        ddadap@nvidia.com, kai.heng.feng@canonical.com,
        Dell.Client.Kernel@dell.com
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On Fri, Aug 19, 2022 at 4:25 PM Mario Limonciello
<mario.limonciello@amd.com> wrote:
>
> 3 _OSI strings were introduced in recent years that were intended
> to workaround very specific problems found on specific systems.
>
> The idea was supposed to be that these quirks were only used on
> those systems, but this proved to be a bad assumption.  I've found
> at least one system in the wild where the vendor using the _OSI
> string doesn't match the _OSI string and the neither does the use.
>
> So this brings a good time to review keeping those strings in the kernel.
> There are 3 strings that were introduced:
>
> Linux-Dell-Video
> -> Intended for systems with NVIDIA cards that didn't support RTD3
> Linux-Lenovo-NV-HDMI-Audio
> -> Intended for powering on NVIDIA HDMI device
> Linux-HPI-Hybrid-Graphics
> -> Intended for changing dGPU output
>
> AFAIK the first string is no longer relevant as nouveau now supports
> RTD3.  If that's wrong, this can be changed for the series.
>

Nouveau always supported RTD3, because that's mainly a kernel feature.
When those were introduced we simply had a bug only hit on a few
systems. And instead of helping us to debug this, this workaround was
added :( We were not even asked about this.

I am a bit curious about the other two though as I am not even sure
they are needed at all as we put other work arounds in place. @Lyude
Paul might know more about these.