linux-kernel - Re: [PATCH v1] usb: typec: tcpm: Add additional checks for contaminant

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Message-ID: <CAPTae5Lz+QVfXxRb4+anaQau=SXkNHMN9YWwTZ2A_Jt5VnAjtQ@mail.gmail.com>
Date:   Sat, 14 Oct 2023 22:30:11 -0700
From:   Badhri Jagan Sridharan <badhri@...gle.com>
To:     gregkh@...uxfoundation.org, linux@...ck-us.net,
        heikki.krogerus@...ux.intel.com
Cc:     kyletso@...gle.com, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, rdbabiera@...gle.com,
        amitsd@...gle.com, stable@...r.kernel.org
Subject: Re: [PATCH v1] usb: typec: tcpm: Add additional checks for contaminant

Ignore this version. Forgot to run checkpatch. Sending in v2.

Regards,
Badhri

On Sat, Oct 14, 2023 at 10:15 PM Badhri Jagan Sridharan
<badhri@...gle.com> wrote:
>
> When transitioning from SNK_DEBOUNCED to unattached, its worthwhile to
> check for contaminant to mitigate wakeups.
>
> ```
> [81334.219571] Start toggling
> [81334.228220] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [81334.305147] CC1: 0 -> 0, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected]
> [81334.305162] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [81334.305187] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
> [81334.475515] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms]
> [81334.486480] CC1: 0 -> 0, CC2: 3 -> 0 [state SNK_DEBOUNCED, polarity 0, disconnected]
> [81334.486495] state change SNK_DEBOUNCED -> SNK_DEBOUNCED [rev3 NONE_AMS]
> [81334.486515] pending state change SNK_DEBOUNCED -> SNK_UNATTACHED @ 20 ms [rev3 NONE_AMS]
> [81334.506621] state change SNK_DEBOUNCED -> SNK_UNATTACHED [delayed 20 ms]
> [81334.506640] Start toggling
> [81334.516972] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [81334.592759] CC1: 0 -> 0, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected]
> [81334.592773] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [81334.592792] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
> [81334.762940] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms]
> [81334.773557] CC1: 0 -> 0, CC2: 3 -> 0 [state SNK_DEBOUNCED, polarity 0, disconnected]
> [81334.773570] state change SNK_DEBOUNCED -> SNK_DEBOUNCED [rev3 NONE_AMS]
> [81334.773588] pending state change SNK_DEBOUNCED -> SNK_UNATTACHED @ 20 ms [rev3 NONE_AMS]
> [81334.793672] state change SNK_DEBOUNCED -> SNK_UNATTACHED [delayed 20 ms]
> [81334.793681] Start toggling
> [81334.801840] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [81334.878655] CC1: 0 -> 0, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected]
> [81334.878672] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [81334.878696] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
> [81335.048968] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms]
> [81335.060684] CC1: 0 -> 0, CC2: 3 -> 0 [state SNK_DEBOUNCED, polarity 0, disconnected]
> [81335.060754] state change SNK_DEBOUNCED -> SNK_DEBOUNCED [rev3 NONE_AMS]
> [81335.060775] pending state change SNK_DEBOUNCED -> SNK_UNATTACHED @ 20 ms [rev3 NONE_AMS]
> [81335.080884] state change SNK_DEBOUNCED -> SNK_UNATTACHED [delayed 20 ms]
> [81335.080900] Start toggling
> ```
>
> Cc: stable@...r.kernel.org
> Fixes: 00bdc7e4e0f56 ("usb: typec: tcpm: Add callbacks to mitigate wakeups due to contaminant")
> Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 6e843c511b85..3634f9092a84 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -3903,7 +3903,9 @@ static void run_state_machine(struct tcpm_port *port)
>                 port->potential_contaminant = ((port->enter_state == SRC_ATTACH_WAIT &&
>                                                 port->state == SRC_UNATTACHED) ||
>                                                (port->enter_state == SNK_ATTACH_WAIT &&
> -                                               port->state == SNK_UNATTACHED));
> +                                               port->state == SNK_UNATTACHED) ||
> +                                              (port->enter_state == SNK_DEBOUNCED &&
> +                                               port->state == SNK_UNATTACHED));
>
>         port->enter_state = port->state;
>         switch (port->state) {
>
> base-commit: 1034cc423f1b4a7a9a56d310ca980fcd2753e11d
> --
> 2.42.0.655.g421f12c284-goog
>