On Wed, Jul 26, 2023 at 02:09:02AM +0000, RD Babiera wrote:
> 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@xxxxxxxxxxxxxxx
> Signed-off-by: RD Babiera <rdbabiera@xxxxxxxxxx>
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/typec/altmodes/displayport.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index 66de880b28d0..cdf8261e22db 100644
> --- 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(struct dp_altmode *dp)
> 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 dp_altmode *dp)
> {
> 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);
> }
>
> base-commit: fdf0eaf11452d72945af31804e2a1048ee1b574c
> --
> 2.41.0.487.g6d72f3e995-goog
--
heikki
