Re: [RFC PATCH v2] media: Virtual camera driver

[Jarkko Sakkinen <jarkko@kernel.org>]

On Tue, Feb 03, 2026 at 08:53:13PM +0200, Jani Nikula wrote:
> On Tue, 03 Feb 2026, johannes.goede@oss.qualcomm.com wrote:
> > OTHO evdi: https://github.com/DisplayLink/evdi has been kept out
> > of the kernel for pretty much the same reasons by the drm/kms folks.
> >
> > At least AFAIK there still is no way to present virtual kms capable
> > display outputs backed by userspace in the kernel.
> >
> > I completely understand where you're coming from wrt v4l2-loopback
> > support (or something equivalent) but asking for this really is
> > the same as asking for the evdi driver to get merged, which AFAIK
> > has been blocked for the reason of avoiding proprietary userspace
> > display output drivers (I guess there might be technical reasons too).
> 
> I'm not sure this is the same thing, though.
> 
> The DRM subsystem does require an open source userspace for new uAPI,
> which is stricter than most subsystems [1]. Other than that, I don't
> think anyone's actively keeping evdi out of the kernel. AFAIK there
> hasn't been a serious attempt at upstreaming it either. Which is pretty
> much because there's no open userspace. Nobody's cared enough to either
> write one or open source the existing one for a decade [2].

This is unrelated of ACK/NACK and not saying this as a "selling point"
but realistically speaking based on what I've read I have extremely hard
time to believe that my driver would enable a market of proprietary
camera drivers :-) Actually, after looking up mipi.org based on Hans
response, I even more so believe that this is the case.

> BR,
> Jani.

BR, Jarkko