[PATCH 0/5] drm/msm/dp: Add MSM Type-C MST support

[Yongxing Mou]

The bridge connector framework currently treats every HPD notification
as a connector state update and emits a userspace hotplug event.
Once MST is enabled, however, connector creation, removal and hotplug
handling are already managed by the DRM DP MST topology manager.

As a result:

  - the SST connector may transiently transition between connected and
    disconnected during MST initialization

  - MST IRQ notifications may generate duplicate userspace hotplug
    events, once from the bridge connector layer and once from the MST
    topology manager

Introduce explicit support for IRQ-only HPD notifications in the bridge
connector framework and allow bridge drivers to suppress connector
hotplug events when those events are already handled elsewhere.

MSM DP uses these mechanisms to integrate Type-C MST hubs without
generating duplicate or spurious userspace hotplug notifications.

Testing
-------
Tested on Hamoa-EVK with a Type-C MST hub and dual-monitor setup.
Both fbcon and Weston were exercised. No duplicate hotplug events,
connector state oscillation or display flickering were observed after
hub attachment.

Dependencies
------------
This patch series was made on top of:

[1] drm: handle IRQ_HPD events correctly (v4)
    https://lore.kernel.org/r/20260608-hpd-irq-events-v4-0-30b62b335487@xxxxxxxxxxxxxxxx

[2] drm/msm/dp: Add MST support for MSM chipsets (v5)
    https://patchwork.freedesktop.org/series/142207/#rev5

[3] drm/msm/dp: Prerequisite cleanup for upcoming MST support (v7)
    https://lore.kernel.org/r/20260609-dp_mstclean-v7-0-ea04113e8233@xxxxxxxxxxxxxxxx

Signed-off-by: Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>
---
Yongxing Mou (5):
      drm/bridge: allow hpd_notify() to suppress connector hotplug events
      drm/bridge_connector: preserve connector status for IRQ-only HPD events
      drm/msm/dp: suppress bridge hotplug events during MST operation
      drm/msm/dp: report IRQ_HPD as an IRQ-only notification
      drm/msm/dp: mark the SST connector disconnected when MST is enabled

 drivers/gpu/drm/bridge/lontium-lt9611uxc.c     |  3 +-
 drivers/gpu/drm/display/drm_bridge_connector.c | 31 ++++++++++++++++-----
 drivers/gpu/drm/meson/meson_encoder_hdmi.c     |  3 +-
 drivers/gpu/drm/msm/dp/dp_display.c            | 38 +++++++++++++++-----------
 drivers/gpu/drm/msm/dp/dp_drm.h                |  3 +-
 drivers/gpu/drm/omapdrm/dss/hdmi4.c            |  3 +-
 drivers/soc/qcom/pmic_glink_altmode.c          | 14 ++++++----
 include/drm/drm_bridge.h                       |  3 +-
 8 files changed, 65 insertions(+), 33 deletions(-)
---
base-commit: e7d700e14934e68f86338c5610cf2ae76798b663
change-id: 20260629-msm-dp-msttypec-b420df7da587
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Best regards,
-- 
Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>