On Tue, Aug 11, 2020 at 6:44 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > 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 My bad ! Apologies Guenter ! Screwed up while performing the git send-email command. Will make sure that I double check next time. Thanks, Badhri > > > 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; > >>>>>>>>> > >>>>>>>> > >>>> > >> >
