From: Kyle Tso kyletso@google.com
commit 2b537cf877eae6d2f2f102052290676e40b74a1d upstream.
If the voltage is being decreased in power negotiation, the Source will set the power supply to operate at the new voltage level before sending PS_RDY. Relax the threshold before sending Request Message so that it will not race with Source which begins to adjust the voltage right after it sends Accept Message (PPS) or tSrcTransition (25~35ms) after it sends Accept Message (non-PPS).
The real threshold will be set after Sink receives PS_RDY Message.
Fixes: f321a02caebd ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support") Cc: stable stable@vger.kernel.org Cc: Badhri Jagan Sridharan badhri@google.com Reviewed-by: Badhri Jagan Sridharan badhri@google.com Acked-by: Heikki Krogerus heikki.krogerus@linux.intel.com Signed-off-by: Kyle Tso kyletso@google.com Link: https://lore.kernel.org/r/20210616090102.1897674-1-kyletso@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/typec/tcpm/tcpm.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)
--- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -2576,6 +2576,11 @@ static void tcpm_pd_ctrl_request(struct } else { next_state = SNK_WAIT_CAPABILITIES; } + + /* Threshold was relaxed before sending Request. Restore it back. */ + tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_PD, + port->pps_data.active, + port->supply_voltage); tcpm_set_state(port, next_state, 0); break; case SNK_NEGOTIATE_PPS_CAPABILITIES: @@ -2589,6 +2594,11 @@ static void tcpm_pd_ctrl_request(struct port->send_discover) port->vdm_sm_running = true;
+ /* Threshold was relaxed before sending Request. Restore it back. */ + tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_PD, + port->pps_data.active, + port->supply_voltage); + tcpm_set_state(port, SNK_READY, 0); break; case DR_SWAP_SEND: @@ -3308,6 +3318,12 @@ static int tcpm_pd_send_request(struct t if (ret < 0) return ret;
+ /* + * Relax the threshold as voltage will be adjusted after Accept Message plus tSrcTransition. + * It is safer to modify the threshold here. + */ + tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, 0); + memset(&msg, 0, sizeof(msg)); msg.header = PD_HEADER_LE(PD_DATA_REQUEST, port->pwr_role, @@ -3405,6 +3421,9 @@ static int tcpm_pd_send_pps_request(stru if (ret < 0) return ret;
+ /* Relax the threshold as voltage will be adjusted right after Accept Message. */ + tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, 0); + memset(&msg, 0, sizeof(msg)); msg.header = PD_HEADER_LE(PD_DATA_REQUEST, port->pwr_role, @@ -4186,6 +4205,10 @@ static void run_state_machine(struct tcp port->hard_reset_count = 0; ret = tcpm_pd_send_request(port); if (ret < 0) { + /* Restore back to the original state */ + tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_PD, + port->pps_data.active, + port->supply_voltage); /* Let the Source send capabilities again. */ tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0); } else { @@ -4196,6 +4219,10 @@ static void run_state_machine(struct tcp case SNK_NEGOTIATE_PPS_CAPABILITIES: ret = tcpm_pd_send_pps_request(port); if (ret < 0) { + /* Restore back to the original state */ + tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_PD, + port->pps_data.active, + port->supply_voltage); port->pps_status = ret; /* * If this was called due to updates to sink