On 8/11/20 6:08 PM, Badhri Jagan Sridharan wrote: > Yes I did ! https://lkml.org/lkml/2020/8/11/788 ! > > For me gmail is grouping V1 and V2 patches in the same thread so > thought you saw the v2 patch :P > You copied me on v1, but not on v2. I am not on any of the mailing lists you sent v2 to, so I did not see it. Guenter > Thanks, > Badhri > > On Tue, Aug 11, 2020 at 5:36 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: >> >> On 8/11/20 4:21 PM, Badhri Jagan Sridharan wrote: >>> Thanks Guenter ! However I don't see a reviewed-by tag :) >>> >> >> Confused. Did you send a v2 with the changes we discussed ? >> I didn't see that. >> >> Thanks, >> Guenter >> >>> On Tue, Aug 11, 2020 at 1:18 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: >>>> >>>> On 8/11/20 12:39 PM, Badhri Jagan Sridharan wrote: >>>>> On Tue, Aug 11, 2020 at 11:45 AM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: >>>>>> >>>>>> On Tue, Aug 11, 2020 at 11:24:07AM -0700, Badhri Jagan Sridharan wrote: >>>>>>> On Mon, Aug 10, 2020 at 6:51 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: >>>>>>>> >>>>>>>> On 8/10/20 6:11 PM, Badhri Jagan Sridharan wrote: >>>>>>>>> >From the spec: >>>>>>>>> "7.1.5 Response to Hard Resets >>>>>>>>> Hard Reset Signaling indicates a communication failure has occurred and >>>>>>>>> the Source Shall stop driving VCONN, Shall remove Rp from the VCONN pin >>>>>>>>> and Shall drive VBUS to vSafe0V as shown in Figure 7-9. The USB connection >>>>>>>>> May reset during a Hard Reset since the VBUS voltage will be less than >>>>>>>>> vSafe5V for an extended period of time. After establishing the vSafe0V >>>>>>>>> voltage condition on VBUS, the Source Shall wait tSrcRecover before >>>>>>>>> re-applying VCONN and restoring VBUS to vSafe5V. A Source Shall conform >>>>>>>>> to the VCONN timing as specified in [USB Type-C 1.3]." >>>>>>>>> >>>>>>>>> Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx> >>>>>>>>> --- >>>>>>>>> drivers/usb/typec/tcpm/tcpm.c | 16 +++++++++++++--- >>>>>>>>> 1 file changed, 13 insertions(+), 3 deletions(-) >>>>>>>>> >>>>>>>>> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c >>>>>>>>> index 3ef37202ee37..e41c4e5d3c71 100644 >>>>>>>>> --- a/drivers/usb/typec/tcpm/tcpm.c >>>>>>>>> +++ b/drivers/usb/typec/tcpm/tcpm.c >>>>>>>>> @@ -3372,13 +3372,19 @@ static void run_state_machine(struct tcpm_port *port) >>>>>>>>> tcpm_set_state(port, SNK_HARD_RESET_SINK_OFF, 0); >>>>>>>>> break; >>>>>>>>> case SRC_HARD_RESET_VBUS_OFF: >>>>>>>>> - tcpm_set_vconn(port, true); >>>>>>>>> + /* >>>>>>>>> + * 7.1.5 Response to Hard Resets >>>>>>>>> + * Hard Reset Signaling indicates a communication failure has occurred and the >>>>>>>>> + * Source Shall stop driving VCONN, Shall remove Rp from the VCONN pin and Shall >>>>>>>>> + * drive VBUS to vSafe0V as shown in Figure 7-9. >>>>>>>>> + */ >>>>>>>>> + tcpm_set_vconn(port, false); >>>>>>>>> tcpm_set_vbus(port, false); >>>>>>>>> tcpm_set_roles(port, port->self_powered, TYPEC_SOURCE, >>>>>>>>> tcpm_data_role_for_source(port)); >>>>>>>>> - tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER); >>>>>>>> >>>>>>>> I am a bit concerned about this. If I understand correctly, it means that >>>>>>>> we won't turn VBUS back on unless a SRC_HARD_RESET_VBUS_OFF PD event is received. >>>>>>>> Is that correct ? What happens if that event is never received ? >>>>>>>> >>>>>>>> Thanks, >>>>>>>> Guenter >>>>>>> >>>>>>> The term PD event is a little ambiguous to me. Trying to summarize the workflow. >>>>>>> Lower level tcpc driver would have to call tcpm_vbus_change which >>>>>>> would in-turn trigger TCPM_VBUS_EVENT >>>>>>> and queries port->tcpc->get_vbus to get the vbus status. It is not >>>>>>> really a PD protocol driven event hence the >>>>>>> confusion. >>>>>>> >>>>>>> "What happens if that event is never received ?" >>>>>>> Yeah TCPM would be in SRC_HARD_RESET_VBUS_OFF till the tcpc calls the >>>>>>> tcpm_vbus_change. >>>>>>> Do you suspect that existing tcpc would not have the capability to >>>>>>> monitor vbus status while sourcing and call tcpm_vbus_change? >>>>>>> >>>>>> That, or the driver might be buggy, or the hardware does't signal a status >>>>>> update, or the update gets lost. I think we should have some backup, >>>>>> to trigger if the event is not received in a reasonable amout of time. >>>>>> I don't know if the specification has some kind of maximum limit. If >>>>>> not, we should still have something >>>>>> >>>>>> Thanks, >>>>>> Guenter >>>>> >>>>> Got it ! The specification actually has a bound for vbus off. >>>>> tSafe0V - Time to reach vSafe0V max - 650ms. (PD_T_SAFE_0V). >>>>> So I will bound it to that. >>>>> >>>> >>>> Excellent. Thanks a lot for looking into this! >>>> >>>> Guenter >>>> >>>>> >From Table 7-12 Sequence Description for a Source Initiated Hard Reset: >>>>> 4.Policy Engine waits tPSHardReset after sending Hard Reset Signaling >>>>> and then tells the Device Policy Manager to instruct the power supply >>>>> to perform a Hard Reset. The transition to vSafe0V Shall occur within >>>>> tSafe0V (t2). >>>>> 5 After tSrcRecover the Source applies power to VBUS in an attempt to >>>>> re-establish communication with the Sink and resume USB Default >>>>> Operation. The transition to vSafe5V Shall occur within tSrcTurnOn >>>>> (t4). >>>>> >>>>> Thanks, >>>>> Badhri >>>>> >>>>>> >>>>>>> Thanks, >>>>>>> Badhri >>>>>>> >>>>>>> >>>>>>>>> break; >>>>>>>>> case SRC_HARD_RESET_VBUS_ON: >>>>>>>>> + tcpm_set_vconn(port, true); >>>>>>>>> tcpm_set_vbus(port, true); >>>>>>>>> port->tcpc->set_pd_rx(port->tcpc, true); >>>>>>>>> tcpm_set_attached_state(port, true); >>>>>>>>> @@ -3944,7 +3950,11 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port) >>>>>>>>> tcpm_set_state(port, SNK_HARD_RESET_WAIT_VBUS, 0); >>>>>>>>> break; >>>>>>>>> case SRC_HARD_RESET_VBUS_OFF: >>>>>>>>> - tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, 0); >>>>>>>>> + /* >>>>>>>>> + * After establishing the vSafe0V voltage condition on VBUS, the Source Shall wait >>>>>>>>> + * tSrcRecover before re-applying VCONN and restoring VBUS to vSafe5V. >>>>>>>>> + */ >>>>>>>>> + tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER); >>>>>>>>> break; >>>>>>>>> case HARD_RESET_SEND: >>>>>>>>> break; >>>>>>>>> >>>>>>>> >>>> >>
