Guenter Roeck <linux@xxxxxxxxxxxx> 於 2020年9月3日 週四 上午12:57寫道： > > On Wed, Sep 02, 2020 at 11:35:33PM +0800, cy_huang wrote: > > From: ChiYuan Huang <cy_huang@xxxxxxxxxxx> > > > > Fix: If vbus event is before cc_event trigger, hard_reset_count > > won't bt reset for some case. > > > > Signed-off-by: ChiYuan Huang <cy_huang@xxxxxxxxxxx> > > --- > > Below's the flow. > > > > _tcpm_pd_vbus_off() -> run_state_machine to change state to SNK_UNATTACHED > > call tcpm_snk_detach() -> tcpm_snk_detach() -> tcpm_detach() > > tcpm_port_is_disconnected() will be called. > > But port->attached is still true and port->cc1=open and port->cc2=open > > > > It cause tcpm_port_is_disconnected return false, then hard_reset_count won't be reset. > > After that, tcpm_reset_port() is called. > > port->attached become false. > > > > After that, cc now trigger cc_change event, the hard_reset_count will be kept. > > Even tcpm_detach will be called, due to port->attached is false, tcpm_detach() > > will directly return. > > > > CC_EVENT will only trigger drp toggling again. > > --- > > drivers/usb/typec/tcpm/tcpm.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > > index a48e3f90..5c73e1d 100644 > > --- a/drivers/usb/typec/tcpm/tcpm.c > > +++ b/drivers/usb/typec/tcpm/tcpm.c > > @@ -2797,8 +2797,7 @@ static void tcpm_detach(struct tcpm_port *port) > > port->tcpc->set_bist_data(port->tcpc, false); > > } > > > > - if (tcpm_port_is_disconnected(port)) > > - port->hard_reset_count = 0; > > + port->hard_reset_count = 0; > > > > Doesn't that mean that the state machine will never enter > error recovery ? > I think it does't affect the error recovery. All error recovery seems to check pd_capable flag. >From my below case, it's A to C cable only. There is no USBPD contract will be estabilished. This case occurred following by the below test condition Cable -> A to C (default Rp bind to vbus) connected to PC. 1. first time plugged in the cable with PC It will make HARD_RESET_COUNT to be equal 2 2. And then plug out. At that time HARD_RESET_COUNT is till 2. 3. next time plugged in again. Due to hard_reset_count is still 2 , after wait_cap_timeout, the state eventually changed to SNK_READY. But during the state transition, no hard_reset be sent. Defined in the USBPD policy engine, typec transition to USBPD, all variables must be reset included hard_reset_count. So it expected SNK must send hard_reset again. The original code defined hard_reset_count must be reset only when tcpm_port_is_disconnected. It doesn't make sense that it only occurred in some scenario. If tcpm_detach is called, hard_reset count must be reset also. > Guenter > > > tcpm_reset_port(port); > > } > > -- > > 2.7.4 > >
