[PATCH 6.1 121/131] usb: typec: altmodes/displayport: Signal hpd low when exiting mode

Greg Kroah-Hartman
2023-10-16T09:05:54Z

From: RD Babiera <rdbabiera@google.com>

commit 89434b069e460967624903b049e5cf5c9e6b99b9 upstream.

Upon receiving an ACK for a sent EXIT_MODE message, the DisplayPort
driver currently resets the status and configuration of the port partner.
The hpd signal is not updated despite being part of the status, so the
Display stack can still transmit video despite typec_altmode_exit placing
the lanes in a Safe State.

Set hpd to low when a sent EXIT_MODE message is ACK'ed.

Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable@vger.kernel.org
Signed-off-by: RD Babiera <rdbabiera@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20231009210057.3773877-2-rdbabiera@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/typec/altmodes/displayport.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -301,6 +301,11 @@ static int dp_altmode_vdm(struct typec_a
case CMD_EXIT_MODE:
dp->data.status = 0;
dp->data.conf = 0;
+ if (dp->hpd) {
+ drm_connector_oob_hotplug_event(dp->connector_fwnode);
+ dp->hpd = false;
+ sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
+ }
break;
case DP_CMD_STATUS_UPDATE:
dp->data.status = *vdo;