[PATCH v2] drm/vkms: add module parameter to set background color

[Daniel Vetter]

On Tue, Apr 11, 2023 at 08:58:16AM +0000, Simon Ser wrote:
> Hi,
> 
> On Monday, April 10th, 2023 at 19:50, Melissa Wen <mwen at igalia.com> wrote:
> 
> > On 04/10, Simon Ser wrote:
> > 
> > > I think this should be a KMS property instead of a module parameter.
> > > Is there a reason why this patch uses a module parameter? It breaks
> > > user-space expectations.
> > 
> > a KMS property is what we have on vkms TODO [1] and the module parameter
> > was Maíra's first step to open a discussion for this property [2].
> > AFAIK, we would need to create the KMS property first, but it seems
> > there isn't an userspace case/need to support this API change.
> > Do you know any valid use cases to support a bkg color property?
> 
> There have been previous attempts for msm [1] and i915 [2].
> 
> From user-space PoV, a KMS property would be useful, for instance to
> render single color background images. I can type some user-space code
> if that helps.

Yeah the hold-up thus far was that no one ever came up with an actually
useful use in a compositor for this. Everyone seems happy with black, but
maybe with proper color rendering this is changing :-)

> If this is a module parameter instead of a KMS property, what purpose
> does this achieve? What is the use-case? Just trying to understand the
> motivation here.

Just a step to get things going, occasionally that's needed ...
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch