From: RD Babiera rdbabiera@google.com
commit 5a5ccd61cfd76156cb3e0373c300c509d05448ce upstream.
When connecting to some DisplayPort partners, the initial status update after entering DisplayPort Alt Mode notifies that the DFP_D/UFP_D is not in the connected state. This leads to sending a configure message that keeps the device in USB mode. The port partner then sets DFP_D/UFP_D to the connected state and HPD to high in the same Attention message. Currently, the HPD signal is dropped in order to handle configuration.
This patch saves changes to the HPD signal when the device chooses to configure during dp_altmode_status_update, and invokes sysfs_notify if necessary for HPD after configuring.
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/20230726020903.1409072-1-rdbabiera@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/typec/altmodes/displayport.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)
--- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -60,6 +60,7 @@ struct dp_altmode {
enum dp_state state; bool hpd; + bool pending_hpd;
struct mutex lock; /* device lock */ struct work_struct work; @@ -144,8 +145,13 @@ static int dp_altmode_status_update(stru dp->state = DP_STATE_EXIT; } else if (!(con & DP_CONF_CURRENTLY(dp->data.conf))) { ret = dp_altmode_configure(dp, con); - if (!ret) + if (!ret) { dp->state = DP_STATE_CONFIGURE; + if (dp->hpd != hpd) { + dp->hpd = hpd; + dp->pending_hpd = true; + } + } } else { if (dp->hpd != hpd) { drm_connector_oob_hotplug_event(dp->connector_fwnode); @@ -161,6 +167,16 @@ static int dp_altmode_configured(struct { sysfs_notify(&dp->alt->dev.kobj, "displayport", "configuration"); sysfs_notify(&dp->alt->dev.kobj, "displayport", "pin_assignment"); + /* + * If the DFP_D/UFP_D sends a change in HPD when first notifying the + * DisplayPort driver that it is connected, then we wait until + * configuration is complete to signal HPD. + */ + if (dp->pending_hpd) { + drm_connector_oob_hotplug_event(dp->connector_fwnode); + sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd"); + dp->pending_hpd = false; + }
return dp_altmode_notify(dp); }