Hi Xu,
On Mon, Feb 19, 2024 at 08:36:50AM +0000, Xu Yang wrote:
> > Connecting an unpowered USB-C 4-port HUB:
> >
> > Before reverting this patch: (endless loop)
> >
> > [ 0.657246] Setting usb_comm capable false
> > [ 0.661870] Setting voltage/current limit 0 mV 0 mA
> > [ 0.661880] polarity 0
> > [ 0.661883] Requesting mux state 0, usb-role 0, orientation 0
> > [ 0.663879] state change INVALID_STATE -> SNK_UNATTACHED [rev1 NONE_AMS]
> > [ 0.663891] CC1: 0 -> 0, CC2: 0 -> 0 [state SNK_UNATTACHED, polarity 0, disconnected]
> > [ 0.663897] 4-0022: registered
> > [ 0.663962] Setting usb_comm capable false
> > [ 0.669903] Setting voltage/current limit 0 mV 0 mA
> > [ 0.669914] polarity 0
> > [ 0.669917] Requesting mux state 0, usb-role 0, orientation 0
> > [ 0.672166] cc:=2
> > [ 0.679360] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [rev1 NONE_AMS]
> > [ 0.779554] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms]
> > [ 0.779570] state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED [rev1 NONE_AMS]
> > [ 0.779576] Start toggling
> > [ 12.957711] CC1: 0 -> 0, CC2: 0 -> 2 [state TOGGLING, polarity 0, connected]
> > [ 12.957720] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
> > [ 12.957729] pending state change SRC_ATTACH_WAIT -> SNK_TRY @ 200 ms [rev1 NONE_AMS]
> > [ 13.157924] state change SRC_ATTACH_WAIT -> SNK_TRY [delayed 200 ms]
> > [ 13.157939] cc:=2
> > [ 13.167339] pending state change SNK_TRY -> SNK_TRY_WAIT @ 100 ms [rev1 NONE_AMS]
> > [ 13.267545] state change SNK_TRY -> SNK_TRY_WAIT [delayed 100 ms]
> > [ 13.267561] state change SNK_TRY_WAIT -> SRC_TRYWAIT [rev1 NONE_AMS]
> > [ 13.267566] cc:=3
> > [ 13.278148] pending state change SRC_TRYWAIT -> SRC_TRYWAIT_UNATTACHED @ 100 ms [rev1 NONE_AMS]
>
> Based on my assumption, the DRP port is presenting Rp-default termination on CC line again,
> then tcpc should report CC change due to a connection is established in 100 ms. However, this
> CC change is not reported here. This leads to state from SRC_TRYWAIT to SRC_TRYWAIT_UNATTACHED
> rather SRC_TRYWAIT_DEBOUNCE.
>
> Below log is a normal case.
>
> ---
> [ 149.954434] CC1: 0 -> 0, CC2: 0 -> 2 [state TOGGLING, polarity 0, connected]
> [ 149.954447] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
> [ 149.954452] pending state change SRC_ATTACH_WAIT -> SNK_TRY @ 200 ms [rev1 NONE_AMS]
> [ 150.154543] state change SRC_ATTACH_WAIT -> SNK_TRY [delayed 200 ms]
> [ 150.154554] cc:=2
> [ 150.154859] pending state change SNK_TRY -> SNK_TRY_WAIT @ 100 ms [rev1 NONE_AMS]
> [ 150.254881] state change SNK_TRY -> SNK_TRY_WAIT [delayed 100 ms]
> [ 150.254893] state change SNK_TRY_WAIT -> SRC_TRYWAIT [rev1 NONE_AMS]
> [ 150.254896] cc:=3
> [ 150.255200] pending state change SRC_TRYWAIT -> SRC_TRYWAIT_UNATTACHED @ 100 ms [rev1 NONE_AMS]
> [ 150.257288] CC1: 0 -> 0, CC2: 2 -> 2 [state SRC_TRYWAIT, polarity 0, connected]
> [ 150.257295] state change SRC_TRYWAIT -> SRC_TRYWAIT_DEBOUNCE [rev1 NONE_AMS]
> [ 150.257300] pending state change SRC_TRYWAIT_DEBOUNCE -> SRC_ATTACHED @ 200 ms [rev1 NONE_AMS]
> [ 150.457319] state change SRC_TRYWAIT_DEBOUNCE -> SRC_ATTACHED [delayed 200 ms]
> [ 150.457329] cc:=3
> [ 150.457606] polarity 1
> [ 150.458314] Requesting mux state 1, usb-role 1, orientation 2
> [ 150.460722] vbus:=1 charge=0
> ---
So I tried with tcpci based system and it works with your patch:
[ 2.644265] Setting usb_comm capable false
[ 2.645756] Setting voltage/current limit 0 mV 0 mA
[ 2.645762] polarity 0
[ 2.647884] Requesting mux state 0, usb-role 0, orientation 0
[ 2.649661] state change INVALID_STATE -> SNK_UNATTACHED [rev1 NONE_AMS]
[ 2.650611] CC1: 0 -> 0, CC2: 0 -> 0 [state SNK_UNATTACHED, polarity 0, disconnected]
[ 2.650617] 2-004e: registered
[ 2.650619] Setting usb_comm capable false
[ 2.652276] Setting voltage/current limit 0 mV 0 mA
[ 2.652282] polarity 0
[ 2.654410] Requesting mux state 0, usb-role 0, orientation 0
[ 2.655799] cc:=2
[ 2.656612] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [rev1 NONE_AMS]
[ 2.656615] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms]
[ 2.656616] state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED [rev1 NONE_AMS]
[ 2.656617] Start toggling
[ 24.268594] CC1: 0 -> 2, CC2: 0 -> 0 [state TOGGLING, polarity 0, connected]
[ 24.268599] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
[ 24.268602] pending state change SRC_ATTACH_WAIT -> SNK_TRY @ 200 ms [rev1 NONE_AMS]
[ 24.468659] state change SRC_ATTACH_WAIT -> SNK_TRY [delayed 200 ms]
[ 24.468664] cc:=2
[ 24.469899] pending state change SNK_TRY -> SNK_TRY_WAIT @ 100 ms [rev1 NONE_AMS]
[ 24.473708] CC1: 2 -> 0, CC2: 0 -> 0 [state SNK_TRY, polarity 0, disconnected]
^^^^ this is extra
[ 24.569964] state change SNK_TRY -> SNK_TRY_WAIT [delayed 100 ms]
[ 24.569968] state change SNK_TRY_WAIT -> SRC_TRYWAIT [rev1 NONE_AMS]
[ 24.569970] cc:=5
[ 24.571089] pending state change SRC_TRYWAIT -> SRC_TRYWAIT_UNATTACHED @ 100 ms [rev1 NONE_AMS]
[ 24.574996] CC1: 0 -> 2, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, connected]
^^^ this is different from your log due to prior change to 0/0
and here the fusb302 backed tcpm would fail/diverge, due to lack of this
line
[ 24.575001] state change SRC_TRYWAIT -> SRC_TRYWAIT_DEBOUNCE [rev1 NONE_AMS]
[ 24.575004] pending state change SRC_TRYWAIT_DEBOUNCE -> SRC_ATTACHED @ 200 ms [rev1 NONE_AMS]
[ 24.775066] state change SRC_TRYWAIT_DEBOUNCE -> SRC_ATTACHED [delayed 200 ms]
.... lack of cc:=5? after => SRC_ATTACHED
[ 24.775070] polarity 0
[ 24.778209] Requesting mux state 1, usb-role 1, orientation 1
[ 24.779236] vbus:=1 charge=0
[ 24.780234] pending state change SRC_ATTACHED -> SRC_UNATTACHED @ 480 ms [rev1 NONE_AMS]
[ 24.782755] VBUS on
[ 24.782758] state change SRC_ATTACHED -> SRC_STARTUP [rev1 NONE_AMS]
[ 24.782773] AMS POWER_NEGOTIATION start
[ 24.782774] cc:=4
[ 24.783540] pending state change SRC_STARTUP -> AMS_START @ 16 ms [rev3 POWER_NEGOTIATION]
[ 24.799554] state change SRC_STARTUP -> AMS_START [delayed 16 ms]
[ 24.799558] state change AMS_START -> SRC_SEND_CAPABILITIES [rev3 POWER_NEGOTIATION]
[ 24.799559] PD TX, header: 0x11a1
[ 24.807710] PD TX complete, status: 2
[ 24.807765] pending state change SRC_SEND_CAPABILITIES -> SRC_SEND_CAPABILITIES @ 150 ms [rev3 POWER_NEGOTIATION]
[ 24.957845] state change SRC_SEND_CAPABILITIES -> SRC_SEND_CAPABILITIES [delayed 150 ms]
So it looks slightly different from your log, but ends up working because
there's an CC change event after "pending state change SRC_TRYWAIT -> SRC_TRYWAIT_UNATTACHED @ 100 ms".
So I think your patch changes some assumptions about the need for the CC change
event in this state, which breaks the state machine. If I strip the logs to just
cc events:
Your normal case:
[ 149.954434] CC1: 0 -> 0, CC2: 0 -> 2 [state TOGGLING, polarity 0, connected]
[ 150.154554] cc:=2
[ 150.254896] cc:=3
[ 150.257288] CC1: 0 -> 0, CC2: 2 -> 2 [state SRC_TRYWAIT, polarity 0, connected]
[ 150.457329] cc:=3
My husb311 working case:
[ 24.268594] CC1: 0 -> 2, CC2: 0 -> 0 [state TOGGLING, polarity 0, connected]
[ 24.468664] cc:=2
[ 24.473708] CC1: 2 -> 0, CC2: 0 -> 0 [state SNK_TRY, polarity 0, disconnected]
[ 24.569970] cc:=5
[ 24.574996] CC1: 0 -> 2, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, connected]
My non-working fusb302 case:
[ 12.957711] CC1: 0 -> 0, CC2: 0 -> 2 [state TOGGLING, polarity 0, connected]
[ 13.157939] cc:=2
[ 13.267566] cc:=3
[ 13.462597] CC1: 0 -> 0, CC2: 2 -> 2 [state TOGGLING, polarity 0, connected]
[ 13.662827] cc:=2
kind regards,
o.
> So the issue may be why that CC change is not reported?
>
> Please refer to USB Type-C Specification
> Figure 4-17 Connection State Diagram: DRP with Accessory and Try.SNK Support
>
> Thanks,
> Xu Yang
>
> > [ 13.378347] state change SRC_TRYWAIT -> SRC_TRYWAIT_UNATTACHED [delayed 100 ms]
> > [ 13.378364] state change SRC_TRYWAIT_UNATTACHED -> SNK_UNATTACHED [rev1 NONE_AMS]
> > [ 13.378373] Start toggling
> > [ 13.387019] state change SNK_UNATTACHED -> TOGGLING [rev1 NONE_AMS]
> > [ 13.462597] CC1: 0 -> 0, CC2: 2 -> 2 [state TOGGLING, polarity 0, connected]
> > [ 13.462606] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
> > [ 13.462613] pending state change SRC_ATTACH_WAIT -> SNK_TRY @ 200 ms [rev1 NONE_AMS]
> > [ 13.662808] state change SRC_ATTACH_WAIT -> SNK_TRY [delayed 200 ms]
> > [ 13.662827] cc:=2
>
