Re: [RFC 0/2] Stop the abuse of Linux-* _OSI strings

From: Limonciello, Mario
Date: Fri Aug 19 2022 - 12:22:38 EST

On 8/19/2022 10:44, Karol Herbst wrote:
On Fri, Aug 19, 2022 at 4:25 PM Mario Limonciello
<mario.limonciello@xxxxxxx> 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.

My apologies, I was certainly part of the impetus for this W/A in the first place while I was at my previous employer. Your comment re-affirms to me that at least the first patch is correct.


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.


If the other two really aren't needed anymore, then yeah we should just tear all 3 out. If that's the direction we go, I would appreciate some commit IDs to reference in the commit message for tearing them out so that if they end up backporting to stable we know how far they should go.