[PATCH] drm/amdgpu/dc: Pixel encoding DRM property and module parameter

[James Ettle]

On 28/09/2020 21:12, Kazlauskas, Nicholas wrote:
> 
> DRM modes don't specify the encoding. The property as part of this patch 
> lets userspace override it but the userspace GUI support isn't there on 
> Wayland IIRC.
> 
> I'm fine with adding the properties but I don't think the module 
> parameter is the right solution here. I think it's better if we try to 
> get this into atomic userspace as well or revive efforts that have been 
> already started before.
> 
> The problem with the module parameters is that it'd be applying a 
> default to every DRM connector. No way to specify different defaults per 
> DRM connector, nor do we know the full connector set at driver 
> initialization. The list is dynamic and can change when you plug/unplug 
> MST displays.
> 
What about using the existing "video=" kernel command-line option? I 
looks like this acts at the DRM level and is a driver-neutral mechanism 
for specifying defaults on a per-connector basis.

It also has a straightforward means for parsing additional arbitrary 
options that could be used -- from what I can make out this would 
require adding pixel encoding to struct drm_cmdline_mode.

Regards,

-James