[PATCH 0/3] drm/display: hdmi: Fix SCDC scrambling corner cases

[Cristian Ciocaltea <cristian.ciocaltea@collabora.com>]

This series fixes a few corner cases in the scrambling helpers
introduced by commit d653818324ed ("drm/display: hdmi: Add HDMI 2.0
scrambling management helpers").

Patch 1 fixes a potential NULL pointer dereference in
drm_connector_hdmi_sync_scdc() reported by Smatch.

Patch 2 makes the SCDC resync logic rely on the committed state
(scrambler_needed) rather than the source-side scrambler_enabled flag.
The flag can be stale after a boot-time disable, which may cause a
spurious CRTC reset and flicker on non-scrambled modes.

Patch 3 ensures the sink's scrambling status is reset on non-scrambled
modesets.  Without this, a sink left scrambling by the firmware may
never be cleared if the first modeset uses a mode below 340 MHz.  The
reset logic is factored into a common helper, which only writes to SCDC
when bits are actually set.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
Cristian Ciocaltea (3):
      drm/display: hdmi: Prevent NULL pointer dereference in sync_scdc()
      drm/display: hdmi: Use committed state to decide on SCDC resync
      drm/display: hdmi: Reset sink scrambling on non-scrambled modesets

 drivers/gpu/drm/display/drm_hdmi_helper.c | 65 ++++++++++++++++++++++++-------
 1 file changed, 50 insertions(+), 15 deletions(-)
---
base-commit: 6628e7d4c6b25c8d18f1345e3a20d21829aae7e4
change-id: 20261104-hdmi-scdc-scramb-fixes-750545a23603