[PATCH v3 0/8] drm/vc4: Add generic helpers for HDMI scrambling

[Maxime Ripard]

Hi,

This is a follow-up of the work to support the interactions between the hotplug
and the scrambling support for vc4:

https://lore.kernel.org/dri-devel/20210507150515.257424-11-maxime@cerno.tech/
https://lore.kernel.org/dri-devel/20211025152903.1088803-10-maxime@cerno.tech/
https://lore.kernel.org/dri-devel/20211118103814.524670-1-maxime@cerno.tech/

Ville feedback was that the same discussion happened some time ago for i915,
and resulted in a function to do an full disable/enable cycle on reconnection
to avoid breaking the HDMI 2.0 spec.

While the previous versions of this series was moving the current scrambling
related functions into generic helpers to consolidate that logic, it proved to
be difficult to rework existing drivers to make use of it without hardware to
test it on and thus the code is (for now) private to vc4.

I still believe that long term, the code to decide if the scrambler needs to be
enabled or not should be moved into a generic helper.

This also means that we would need to move the format output decision to a
generic helper, which also makes sense to me but it probably going to be
controversial.

Let me know what you think,
Maxime

Changes from v2:
  - Rebased on next-20220713
  - Dropped the generic helpers and put them into vc4

Changes from v1:
  - Dropped the 340MHz define
  - Make drm_mode_hdmi_requires_scrambling use the bpc
  - Make more drm_display_mode const in vc4
  - Dropped the tegra conversion
  - Added more comments

Maxime Ripard (8):
  drm/vc4: hdmi: Constify drm_display_mode
  drm/vc4: hdmi: Remove unused argument in vc4_hdmi_supports_scrambling
  drm/vc4: hdmi: Remove mutex in detect
  drm/vc4: hdmi: Simplify the hotplug handling
  drm/vc4: hdmi: Switch to detect_ctx
  drm/vc4: hdmi: Move vc4_hdmi_supports_scrambling() around
  drm/vc4: hdmi: Reset link on hotplug
  drm/scdc: Document hotplug gotchas

 drivers/gpu/drm/display/drm_scdc_helper.c |  13 +
 drivers/gpu/drm/vc4/vc4_hdmi.c            | 309 ++++++++++++++--------
 drivers/gpu/drm/vc4/vc4_hdmi.h            |  12 +-
 3 files changed, 220 insertions(+), 114 deletions(-)

-- 
2.36.1