Aliases for DRI connectors?

[Guillermo Rodriguez]

Hi Pekka,

El vie., 3 abr. 2020 a las 10:14, Pekka Paalanen
(<ppaalanen at gmail.com>) escribió:
>
> On Wed, 1 Apr 2020 14:38:37 -0500
> Matt Hoosier <matt.hoosier at gmail.com> wrote:
>
> > I'm searching for some sort of scheme that will let my DRI master query the
> > set of available connectors and select the one carrying a prearranged
> > designation. The problem I'm trying to solve is to allow deploying one
> > standardized userspace component across a fleet of devices that have
> > varying numbers of displays, with the use cases not always driven on the
> > same connector topologically.
> >
> > I had a look around the properties available on my system's DRI connectors,
> > and nothing immediate jumped out at me. Is there a standard connector
> > property that (assuming I can find the right place in DeviceTree or similar
> > to) that would be a good fit for this?
>
> Hi,
>
> I've never heard of a thing that could accomplish that. DRM connector
> names are not even actually communicated to userspace. What userspace
> sees is connector type (enum) and some counter numbers (which are not
> persistent, so not reliable if you have e.g. multiple DRM drivers
> racing to initialize),

I may be misreading you, but does this mean that the connector names
used in the [output] section of the weston.ini configuration file are
not reliable?
Then what is the proper way to configure one specific (physical)
output in Weston?

BR,

Guillermo

> and then userspace manufactures a connector name
> from those. This has been most painful with Xorg, where the different
> video DDX drivers used to use different conventions in making up the
> names, meaning that if you switched DDXes (e.g. between driver-specific
> driver and modesetting driver), the connector names changed
> invalidating your xorg.conf.
>
> However, the problem of non-persistent connector names has been thought
> of, see e.g.:
> https://lists.freedesktop.org/archives/dri-devel/2019-June/221902.html
> The thread has messages also in July and August.
>
> If you had reliable, persistent connector names (and used e.g. device
> path from udev to reliably identify DRM devices), maybe you could build
> something on top of that?
>
> Though I doubt if maintainers would like your config to be in DT or
> kernel, maybe it needs to be handled in userspace?
>
>
> Thanks,
> pq
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