[PATCH v3 0/3] drm/bridge: display-connector: detect DP state if cable is plugged on boot

[Dmitry Baryshkov]

Unlike the USB-C AltMode handling and unlike the DP controller handling
the HPD on its own, if the display-connector is being used to handle the
HPD pin, DP controller might not be able to get either the HPD
notification nor detect the cable state if the cable is plugged in
before the system has booted.

Make the display-connector send the HPD notifications during system
startup for DisplayPort connectors.

It's typically not a problem for other types of display connectors since
there is no special procedure to detect if the monitor is actually
plugged in or not.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
---
Changes in v3:
- Corrected typos in the commit message (Sashiko)
- Reworked HPD-related bridge locking to remove AB-BA deadlock (Jonas,
  Sashiko)
- Link to v2: https://patch.msgid.link/20260513-dp-connector-hpd-v2-0-42f757bfcbf9@xxxxxxxxxxxxxxxx

Changes in v2:
- Expanded commit message, explaining difference from HDMI (Laurent)
- Link to v1: https://lore.kernel.org/r/20260314-dp-connector-hpd-v1-0-786044cedc17@xxxxxxxxxxxxxxxx

---
Dmitry Baryshkov (3):
      drm/bridge: split hpd_mutex into two mutexes
      drm/bridge: display-connector: don't autoenable HPD IRQ
      drm/bridge: display-connector: trigger initial HPD event for DP

 drivers/gpu/drm/bridge/display-connector.c | 36 ++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_bridge.c               | 16 ++++++++++---
 include/drm/drm_bridge.h                   |  4 ++++
 3 files changed, 53 insertions(+), 3 deletions(-)
---
base-commit: 687da68900cd1a46549f7d9430c7d40346cb86a0
change-id: 20260314-dp-connector-hpd-f069e66bc6af

Best regards,
--  
With best wishes
Dmitry