[PATCH v3 0/3] Send a hotplug when edid changes

[Daniel Vetter]

On Tue, Aug 06, 2019 at 03:55:48PM +0300, Stanislav Lisovskiy wrote:
> This series introduce to drm a way to determine if something else
> except connection_status had changed during probing, which
> can be used by other drivers as well. Another i915 specific part
> uses this approach to determine if edid had changed without
> changing the connection status and send a hotplug event.

Did you read through the entire huge thread on all this (with I think
Paul, Pekka, Ram and some others)? I feel like this is mostly taking that
idea, but not taking a lot of the details we've discussed there.
Specifically I'm not sure how userspace should handle this without also
exposing the epoch counter, or at least generating a hotplug event for the
specific connector. All that and more we discussed there.

And then there's the follow-up question: What's the userspace for this?
Existing expectations are a minefield here, so even if you don't plan to
change userspace we need to know what this is aimed for, and see above I
don't think this is possible to use without userspace changes ...
-Daniel

> 
> Stanislav Lisovskiy (3):
>   drm: Add helper to compare edids.
>   drm: Introduce change counter to drm_connector
>   drm/i915: Send hotplug event if edid had changed.
> 
>  drivers/gpu/drm/drm_connector.c              |  1 +
>  drivers/gpu/drm/drm_edid.c                   | 33 ++++++++++++++++++++
>  drivers/gpu/drm/drm_probe_helper.c           | 29 +++++++++++++++--
>  drivers/gpu/drm/i915/display/intel_dp.c      | 16 +++++++++-
>  drivers/gpu/drm/i915/display/intel_hdmi.c    | 16 ++++++++--
>  drivers/gpu/drm/i915/display/intel_hotplug.c | 21 ++++++++++---
>  include/drm/drm_connector.h                  |  3 ++
>  include/drm/drm_edid.h                       |  9 ++++++
>  8 files changed, 117 insertions(+), 11 deletions(-)
> 
> -- 
> 2.17.1
> 

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