On Wed, Apr 07, 2021 at 01:07:21PM -0700, Badhri Jagan Sridharan wrote: > >From PD Spec: > The Sink Shall transition to Sink Standby before a positive or > negative voltage transition of VBUS. During Sink Standby > the Sink Shall reduce its power draw to pSnkStdby. This allows > the Source to manage the voltage transition as well as > supply sufficient operating current to the Sink to maintain PD > operation during the transition. The Sink Shall > complete this transition to Sink Standby within tSnkStdby > after evaluating the Accept Message from the Source. The > transition when returning to Sink operation from Sink Standby > Shall be completed within tSnkNewPower. The > pSnkStdby requirement Shall only apply if the Sink power draw > is higher than this level. > > The above requirement needs to be met to prevent hard resets > from port partner. > > Without the patch: (5V/3A during SNK_DISCOVERY all the way through > explicit contract) > [ 95.711984] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected] > [ 95.712007] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS] > [ 95.712017] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS] > [ 95.837190] VBUS on > [ 95.882075] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms] > [ 95.882082] state change SNK_DEBOUNCED -> SNK_ATTACHED [rev3 NONE_AMS] > [ 95.882086] polarity 1 > [ 95.883151] set_auto_vbus_discharge_threshold mode:0 pps_active:n vbus:5000 ret:0 > [ 95.883441] enable vbus discharge ret:0 > [ 95.883445] Requesting mux state 1, usb-role 2, orientation 2 > [ 95.883776] state change SNK_ATTACHED -> SNK_STARTUP [rev3 NONE_AMS] > [ 95.883879] pending state change SNK_STARTUP -> SNK_DISCOVERY @ 500 ms [rev3 NONE_AMS] > [ 96.038960] VBUS on > [ 96.383939] state change SNK_STARTUP -> SNK_DISCOVERY [delayed 500 ms] > [ 96.383946] Setting voltage/current limit 5000 mV 3000 mA > [ 96.383961] vbus=0 charge:=1 > [ 96.386044] state change SNK_DISCOVERY -> SNK_WAIT_CAPABILITIES [rev3 NONE_AMS] > [ 96.386309] pending state change SNK_WAIT_CAPABILITIES -> HARD_RESET_SEND @ 450 ms [rev3 NONE_AMS] > [ 96.394404] PD RX, header: 0x2161 [1] > [ 96.394408] PDO 0: type 0, 5000 mV, 3000 mA [E] > [ 96.394410] PDO 1: type 0, 9000 mV, 2000 mA [] > [ 96.394412] state change SNK_WAIT_CAPABILITIES -> SNK_NEGOTIATE_CAPABILITIES [rev2 POWER_NEGOTIATION] > [ 96.394416] Setting usb_comm capable false > [ 96.395083] cc=0 cc1=0 cc2=5 vbus=0 vconn=sink polarity=1 > [ 96.395089] Requesting PDO 1: 9000 mV, 2000 mA > [ 96.395093] PD TX, header: 0x1042 > [ 96.397404] PD TX complete, status: 0 > [ 96.397424] pending state change SNK_NEGOTIATE_CAPABILITIES -> HARD_RESET_SEND @ 60 ms [rev2 POWER_NEGOTIATION] > [ 96.400826] PD RX, header: 0x363 [1] > [ 96.400829] state change SNK_NEGOTIATE_CAPABILITIES -> SNK_TRANSITION_SINK [rev2 POWER_NEGOTIATION] > [ 96.400832] pending state change SNK_TRANSITION_SINK -> HARD_RESET_SEND @ 500 ms [rev2 POWER_NEGOTIATION] > [ 96.577315] PD RX, header: 0x566 [1] > [ 96.577321] Setting voltage/current limit 9000 mV 2000 mA > [ 96.578363] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:9000 ret:0 > [ 96.578370] state change SNK_TRANSITION_SINK -> SNK_READY [rev2 POWER_NEGOTIATION] > > With the patch: > [ 168.398573] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected] > [ 168.398605] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS] > [ 168.398619] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS] > [ 168.522348] VBUS on > [ 168.568676] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms] > [ 168.568684] state change SNK_DEBOUNCED -> SNK_ATTACHED [rev3 NONE_AMS] > [ 168.568688] polarity 1 > [ 168.569867] set_auto_vbus_discharge_threshold mode:0 pps_active:n vbus:5000 ret:0 > [ 168.570158] enable vbus discharge ret:0 > [ 168.570161] Requesting mux state 1, usb-role 2, orientation 2 > [ 168.570504] state change SNK_ATTACHED -> SNK_STARTUP [rev3 NONE_AMS] > [ 168.570634] pending state change SNK_STARTUP -> SNK_DISCOVERY @ 500 ms [rev3 NONE_AMS] > [ 169.070689] state change SNK_STARTUP -> SNK_DISCOVERY [delayed 500 ms] > [ 169.070695] Setting voltage/current limit 5000 mV 3000 mA > [ 169.070702] vbus=0 charge:=1 > [ 169.072719] state change SNK_DISCOVERY -> SNK_WAIT_CAPABILITIES [rev3 NONE_AMS] > [ 169.073145] pending state change SNK_WAIT_CAPABILITIES -> HARD_RESET_SEND @ 450 ms [rev3 NONE_AMS] > [ 169.077162] PD RX, header: 0x2161 [1] > [ 169.077172] PDO 0: type 0, 5000 mV, 3000 mA [E] > [ 169.077178] PDO 1: type 0, 9000 mV, 2000 mA [] > [ 169.077183] state change SNK_WAIT_CAPABILITIES -> SNK_NEGOTIATE_CAPABILITIES [rev2 POWER_NEGOTIATION] > [ 169.077191] Setting usb_comm capable false > [ 169.077753] cc=0 cc1=0 cc2=5 vbus=0 vconn=sink polarity=1 > [ 169.077759] Requesting PDO 1: 9000 mV, 2000 mA > [ 169.077762] PD TX, header: 0x1042 > [ 169.079990] PD TX complete, status: 0 > [ 169.080013] pending state change SNK_NEGOTIATE_CAPABILITIES -> HARD_RESET_SEND @ 60 ms [rev2 POWER_NEGOTIATION] > [ 169.083183] VBUS on > [ 169.084195] PD RX, header: 0x363 [1] > [ 169.084200] state change SNK_NEGOTIATE_CAPABILITIES -> SNK_TRANSITION_SINK [rev2 POWER_NEGOTIATION] > [ 169.084206] Setting standby current 5000 mV @ 500 mA > [ 169.084209] Setting voltage/current limit 5000 mV 500 mA > [ 169.084220] pending state change SNK_TRANSITION_SINK -> HARD_RESET_SEND @ 500 ms [rev2 POWER_NEGOTIATION] > [ 169.260222] PD RX, header: 0x566 [1] > [ 169.260227] Setting voltage/current limit 9000 mV 2000 mA > [ 169.261315] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:9000 ret:0 > [ 169.261321] state change SNK_TRANSITION_SINK -> SNK_READY [rev2 POWER_NEGOTIATION] > [ 169.261570] AMS POWER_NEGOTIATION finished > > Fixes: f0690a25a140b ("staging: typec: USB Type-C Port Manager (tcpm)") > Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx> > --- > drivers/usb/typec/tcpm/tcpm.c | 17 +++++++++++++++++ > include/linux/usb/pd.h | 2 ++ > 2 files changed, 19 insertions(+) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index d1d03ee90d8f..770b2edd9a04 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -4131,6 +4131,23 @@ static void run_state_machine(struct tcpm_port *port) > } > break; > case SNK_TRANSITION_SINK: > + /* From the USB PD spec: > + * "The Sink Shall transition to Sink Standby before a positive or > + * negative voltage transition of VBUS. During Sink Standby > + * the Sink Shall reduce its power draw to pSnkStdby." > + * > + * This is not applicable to PPS though as the port can continue > + * to draw negotiated power without switching to standby. > + */ > + if (port->supply_voltage != port->req_supply_voltage && !port->pps_data.active && > + port->current_limit * port->supply_voltage / 1000 > PD_P_SNK_STDBY_MW) { > + u32 stdby_ma = port->supply_voltage ? PD_P_SNK_STDBY_MW * 1000 / > + port->supply_voltage : 0; Looks like unnecessary condition to me. The first condition can not be true if port->supply_voltage == 0. So I think that should be just: u32 stdby_ma = PD_P_SNK_STDBY_MW * 1000 / port->supply_voltage; Or did I miss something? > + tcpm_log(port, "Setting standby current %u mV @ %u mA", > + port->supply_voltage, stdby_ma); > + tcpm_set_current_limit(port, stdby_ma, port->supply_voltage); > + } > + fallthrough; > case SNK_TRANSITION_SINK_VBUS: > tcpm_set_state(port, hard_reset_state(port), > PD_T_PS_TRANSITION); > diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h > index 70d681918d01..bf00259493e0 100644 > --- a/include/linux/usb/pd.h > +++ b/include/linux/usb/pd.h > @@ -493,4 +493,6 @@ static inline unsigned int rdo_max_power(u32 rdo) > #define PD_N_CAPS_COUNT (PD_T_NO_RESPONSE / PD_T_SEND_SOURCE_CAP) > #define PD_N_HARD_RESET_COUNT 2 > > +#define PD_P_SNK_STDBY_MW 2500 /* 2500 mW */ > + > #endif /* __LINUX_USB_PD_H */ > -- > 2.31.1.295.g9ea45b61b8-goog thanks, -- heikki