[PATCH 1/3] drm: add connector info/property for non-std displays

[Keith Packard]

Daniel Stone <daniel at fooishbar.org> writes:

> Why not add a client cap which hides 'non-standard' displays
> completely from non-aware clients? That way you can keep the connected
> status as is, and clients either never see the HMD or will be able to
> check the property.

Most clients are display servers, and it looks like we're settling on
using the display server as the way to enumerate all of the displays (as
direct enumeration through DRM non-master FDs involve rather drastic
permissions changes in the kernel).

This means that display servers are going to have to change to both see
these displays while keeping them from being part of the desktop. So,
while I guess it might be useful to hide HMD from existing display
servers with a bit like this, I don't think there's any particular
long-term benefit?

> Either way, I'm still not convinced doing this in the kernel makes any
> sense.

fbdev. We want to keep the HMD dark until there's something 'real' to
show on it.

If you accept that fbdev needs to know this, then there's no way to
avoid maintaining a database in the kernel. Maybe what we need is some
way to load additional database entries into the kernel at boot time
from a file in the initrd? And if you want a user-space database too,
then maybe the kernel data should be generated from that and dumped into
the initrd? One version of the truth is hard enough to deal with; I'd
hate to have two.

> We need the shared EDID library anyway in order to deal with the quirk
> tables replicated between the kernel/Xorg currently, so that's going
> to happen pretty soon regardless of whether or not the kernel gets its
> own database.

Yeah, we'll presumably need this support in the Vulkan KHR_display
extension too, so sharing EDID support up in user space between all of
these entities seems like a great idea.

-- 
-keith
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