linux-kernel - Re: [PATCH v2] usb: typec: tcpm: Fix sink caps op current check

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Date:   Sun, 15 Oct 2023 05:30:43 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Badhri Jagan Sridharan <badhri@...gle.com>
Cc:     gregkh@...uxfoundation.org, heikki.krogerus@...ux.intel.com,
        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 v2] usb: typec: tcpm: Fix sink caps op current check

On Sun, Oct 15, 2023 at 03:58:38AM +0000, Badhri Jagan Sridharan wrote:
> TCPM checks for sink caps operational current even when PD is disabled.
> This incorrectly sets tcpm_set_charge() when PD is disabled.
> Check for sink caps only when PD is enabled.
> 
> [   97.572342] Start toggling
> [   97.578949] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [   99.571648] CC1: 0 -> 0, CC2: 0 -> 4 [state TOGGLING, polarity 0, connected]
> [   99.571658] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [   99.571673] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
> [   99.741778] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms]
> [   99.789283] CC1: 0 -> 0, CC2: 4 -> 5 [state SNK_DEBOUNCED, polarity 0, connected]
> [   99.789306] state change SNK_DEBOUNCED -> SNK_DEBOUNCED [rev3 NONE_AMS]
> [   99.903584] VBUS on
> [   99.903591] state change SNK_DEBOUNCED -> SNK_ATTACHED [rev3 NONE_AMS]
> [   99.903600] polarity 1
> [   99.910155] enable vbus discharge ret:0
> [   99.910160] Requesting mux state 1, usb-role 2, orientation 2
> [   99.946791] state change SNK_ATTACHED -> SNK_STARTUP [rev3 NONE_AMS]
> [   99.946798] state change SNK_STARTUP -> SNK_DISCOVERY [rev3 NONE_AMS]
> [   99.946800] Setting voltage/current limit 5000 mV 500 mA
> [   99.946803] vbus=0 charge:=1
> [  100.027139] state change SNK_DISCOVERY -> SNK_READY [rev3 NONE_AMS]
> [  100.027145] Setting voltage/current limit 5000 mV 3000 mA
> [  100.466830] VBUS on
> 
> Cc: stable@...r.kernel.org
> Fixes: 34fde9ec08a3 ("FROMGIT: usb: typec: tcpm: not sink vbus if operational current is 0mA")
> Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
> ---
> Changes since v1:
> * Fix commit title and description to address comments from Guenter Roeck
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 6e843c511b85..994493481c24 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4268,7 +4268,8 @@ static void run_state_machine(struct tcpm_port *port)
>  				current_lim = PD_P_SNK_STDBY_MW / 5;
>  			tcpm_set_current_limit(port, current_lim, 5000);
>  			/* Not sink vbus if operational current is 0mA */
> -			tcpm_set_charge(port, !!pdo_max_current(port->snk_pdo[0]));
> +			tcpm_set_charge(port, port->pd_supported ?
> +					!!pdo_max_current(port->snk_pdo[0]) : true);

Nit:
						!port->pd_supported || pdo_max_current(port->snk_pdo[0]

seems simpler. Otherwise

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

>  
>  			if (!port->pd_supported)
>  				tcpm_set_state(port, SNK_READY, 0);
> 
> base-commit: 1034cc423f1b4a7a9a56d310ca980fcd2753e11d
> -- 
> 2.42.0.655.g421f12c284-goog
>