Hi Amit If the setting "bus-powered" is not set, there is only one way, that Vbus does not go down in init (where we force a Hard_Reset, which sets CC to Open if not bus-powerded). The case where Vbus never goes down and setting Bus-powered is not set is only with a legacy cable/adabter. In that case, we do not have PD compatibility anyway, and have to end up in SNK_READY eventually. So we do the SOFT_RESET if Vbus was never down out of historical reasons and is not needed anymore since tcpm is sending Get_Capabilities (the only reason we send SOFT_RESET if Vbus was never down, is to get capabilities of Source, and that we still do, if Get_Capabilities does not work). As you correctly have pointed out, I have to fix a issue I spotted yesterday as well, that with this Patch, after two hard_resets and then after 3 SoftReset we seem not to end up in SNK_READY, but in SNK_UNNCONECTED -> I have to find a way to check if we try hard reset in SOFT_RESET state after leaving the WAIT_SINK_CAPABILITIES_TIMOUT and in that case send it to SNK_CONNECTED (same as if we would be in state WAIT_SINK_CAPABILITIES or WAIT_SINK_CAPABILITIES_TIMOUT). Maybe we have to count softresets after requesing capabilities and reset it as soon as we are in SNK_READY BTW: I have a patch which I use in the 5.15 version of the driver, where I can get ptn5110 to init correctly without forcing the Hardreset and the manual CC_Change trigger (I changed default state of sink to SNK_DEBOUNCED (where Vbus is checked and if not true sends us to SNK_UNCONNECTED) and added a delay of one second to be shure that IRQ is running when state machine starts) Freundliche Grüsse Best regards Freundliche Grüsse Best regards Freundliche Grüsse Best regards ________________________________________ Von: Amit Sunil Dhamne <amitsd@xxxxxxxxxx> Gesendet: Donnerstag, 24. Oktober 2024 05:13 An: Yanik Fuchs <Yanik.fuchs@xxxxxx>; heikki.krogerus@xxxxxxxxxxxxxxx <heikki.krogerus@xxxxxxxxxxxxxxx>; gregkh@xxxxxxxxxxxxxxxxxxx <gregkh@xxxxxxxxxxxxxxxxxxx>; rdbabiera@xxxxxxxxxx <rdbabiera@xxxxxxxxxx>; linux@xxxxxxxxxxxx <linux@xxxxxxxxxxxx>; kyletso@xxxxxxxxxx <kyletso@xxxxxxxxxx>; badhri@xxxxxxxxxx <badhri@xxxxxxxxxx>; xu.yang_2@xxxxxxx <xu.yang_2@xxxxxxx>; sebastian.reichel@xxxxxxxxxxxxx <sebastian.reichel@xxxxxxxxxxxxx> Cc: linux-usb@xxxxxxxxxxxxxxx <linux-usb@xxxxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx <linux-kernel@xxxxxxxxxxxxxxx> Betreff: Re: [PATCH] usb: typec: tcpm: Prevent Hard_Reset if Vbus was never low ACHTUNG: Dieses E-Mail stammt von einem externen Absender. Prüfe Anhänge oder Links sehr genau! Hi Yanik, On 10/22/24 10:28 AM, Yanik Fuchs wrote: > Good Evening > > Here is a Patch to resolve an issue with TCPM if Vbus was never low. > Please consider that this is one of my first kernel pull requests, I may have missunderstood the process. > > Freundliche Grüsse > Best regards > > > Yanik Fuchs > > --- > > From 604b97b6394b5643394bc63d4ac691c098c99c40 Mon Sep 17 00:00:00 2001 > From: yfu <yanikfuchs@xxxxxx> > Date: Tue, 22 Oct 2024 18:23:18 +0200 > Subject: [PATCH] usb: typec: tcpm: Prevent Hard_Reset if Vbus was never low > > Before this patch, tcpm went into SOFT_RESET state, if Vbus was never low > resulting in Hard_Reset, if power supply does not support USB_PD Soft_Reset. > > In order to prevent this, I remove the Vbus check completely, so that > we go as well into the SNK_WAIT_CAPABILITIES_TIMEOUT state. There, we send > PD_CTRL_GET_SOURCE_CAP which many power supply do support. > (122968f8dda8 usb: typec: tcpm: avoid resets for missing source capability messages) Please refer to https://lore.kernel.org/all/20241024022233.3276995-1-amitsd@xxxxxxxxxx/ as 122968f8dda8 is causing USB Type-C PD compliance failures. > > Additionally, I added SOFT_RESET (instead of Hard_Reset) as Fallback solution > if we still not have gotten any capabilities. Hard_Reset is now only done, > if PD_CTRL_GET_SOURCE_CAP and SOFT_RESET fail to get capabilities. > --- > drivers/usb/typec/tcpm/tcpm.c | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index fc619478200f..c7a59c9f78ee 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -5038,14 +5038,8 @@ static void run_state_machine(struct tcpm_port *port) > * were already in a stable contract before this boot. > * Do this only once. > */ > - if (port->vbus_never_low) { > - port->vbus_never_low = false; > - tcpm_set_state(port, SNK_SOFT_RESET, > + tcpm_set_state(port, SNK_WAIT_CAPABILITIES_TIMEOUT, > PD_T_SINK_WAIT_CAP); > - } else { > - tcpm_set_state(port, SNK_WAIT_CAPABILITIES_TIMEOUT, > - PD_T_SINK_WAIT_CAP); > - } Instead of deleting code, please restrict this behavior to non self powered battery case as this most likely break compliance and may break actual use-cases for other users as a result. If you want you can move stuff around after https://lore.kernel.org/all/20241024022233.3276995-1-amitsd@xxxxxxxxxx/ gets accepted in the following way: ``` if (!port->self_powered) { tcpm_set_state(port, SNK_WAIT_CAPABILITIES_TIMEOUT, PD_T_SINK_WAIT_CAP); break; } if (port->vbus_never_low) { tcpm_set_state(port, SNK_SOFT_RESET, PD_T_SINK_WAIT_CAP); } else { tcpm_set_state(port, hard_reset_state(..), PD_T_SINK_WAIT_CAP); } ``` This way you don't have to execute the SNK_SOFT_RESET flow for non self powered use-case. Thanks, Amit > break; > case SNK_WAIT_CAPABILITIES_TIMEOUT: > /* > @@ -5064,7 +5058,7 @@ static void run_state_machine(struct tcpm_port *port) > * according to the specification. > */ > if (tcpm_pd_send_control(port, PD_CTRL_GET_SOURCE_CAP, TCPC_TX_SOP)) > - tcpm_set_state_cond(port, hard_reset_state(port), 0); > + tcpm_set_state_cond(port, SNK_SOFT_RESET, 0); > else > tcpm_set_state(port, hard_reset_state(port), PD_T_SINK_WAIT_CAP); > break;
