This is a note to let you know that I've just added the patch titled

usb: typec: tcpm: Relax disconnect threshold during power negotiation

to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the usb-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From 2b537cf877eae6d2f2f102052290676e40b74a1d Mon Sep 17 00:00:00 2001

From: Kyle Tso kyletso@google.com Date: Wed, 16 Jun 2021 17:01:02 +0800 Subject: usb: typec: tcpm: Relax disconnect threshold during power negotiation

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(+)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index e11e9227107d..5b22a1c931a9 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -2604,6 +2604,11 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, } 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: @@ -2617,6 +2622,11 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, 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: @@ -3336,6 +3346,12 @@ static int tcpm_pd_send_request(struct tcpm_port *port) 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, @@ -3433,6 +3449,9 @@ static int tcpm_pd_send_pps_request(struct tcpm_port *port) 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, @@ -4196,6 +4215,10 @@ static void run_state_machine(struct tcpm_port *port) 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 { @@ -4206,6 +4229,10 @@ static void run_state_machine(struct tcpm_port *port) 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