[RFC][PATCH 0/2] drm: PATH prop for all connectors?

[Daniel Vetter]

On Thu, Jun 13, 2019 at 09:43:33PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Here's a possible apporoach for providing userspace with
> some stable connector identifiers. Combine with the bus
> name of the GPU and you should have some kind of real
> physical path description. Unfortunately the ship has
> sailed for MST connectors because userspace is already
> parsing the property and expects to find certain things
> there. So if we want stable names for those we'd probably
> have introduce another PATH prop (PHYS_PATH?).
> 
> I suppose one alternative would to make the connector 
> type_id stable. Currently that is being populated by drm 
> core and it's just a global counter. Not sure how badly
> things would turn out if we'd allow each driver to set
> that. It could result in conflicting xrandr connector
> names between different GPUs which I suppose would
> confuse existing userspace?

I think the only reason this global id stuff exists is because with
original xrandr, that stuff was global. And then it got copypasted
forever.

Would need to do a bunch of reviewing, but I'd expect we'll get away with
just making all these allocators per-device.
-Daniel

> 
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Pekka Paalanen <ppaalanen at gmail.com>
> Cc: Ilia Mirkin <imirkin at alum.mit.edu>
> 
> Ville Syrjälä (2):
>   drm: Improve PATH prop docs
>   drm/i915: Populate PATH prop for every connector
> 
>  drivers/gpu/drm/drm_connector.c        | 13 ++++++++--
>  drivers/gpu/drm/i915/icl_dsi.c         |  3 +++
>  drivers/gpu/drm/i915/intel_connector.c | 20 +++++++++++++++
>  drivers/gpu/drm/i915/intel_connector.h |  3 +++
>  drivers/gpu/drm/i915/intel_crt.c       |  2 ++
>  drivers/gpu/drm/i915/intel_dp.c        |  6 ++++-
>  drivers/gpu/drm/i915/intel_dp_mst.c    |  3 +--
>  drivers/gpu/drm/i915/intel_dvo.c       |  3 +++
>  drivers/gpu/drm/i915/intel_hdmi.c      |  4 +++
>  drivers/gpu/drm/i915/intel_lvds.c      |  2 ++
>  drivers/gpu/drm/i915/intel_sdvo.c      | 35 ++++++++++++++++++--------
>  drivers/gpu/drm/i915/intel_tv.c        |  2 ++
>  drivers/gpu/drm/i915/vlv_dsi.c         |  3 +++
>  13 files changed, 83 insertions(+), 16 deletions(-)
> 
> -- 
> 2.21.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch