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From:   Kyle Tso <kyletso@google.com>
Date:   Wed, 13 Jan 2021 22:46:07 +0800
Message-ID: <CAGZ6i=2cQywq82QrJg=t-KVMqSdjME-dkd-8aH3au_RTju2zTA@mail.gmail.com>
Subject: Re: [PATCH v5 1/3] usb: typec: tcpm: AMS and Collision Avoidance
To:     Badhri Jagan Sridharan <badhri@google.com>
Cc:     Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hans de Goede <hdegoede@redhat.com>,
        USB <linux-usb@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Will McVicker <willmcvicker@google.com>
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On Wed, Jan 13, 2021 at 2:11 PM Badhri Jagan Sridharan
<badhri@google.com> wrote:
>
> Hi Kyle,
>
> Do you want to handle the FAST_ROLE_SWAP case as well ?
>
I forgot this part....
Thanks for catching this.
I will fix it.


> You would have to fix up in two places:
>
> #1
> -                       if (port->state == SNK_READY)
> -                               tcpm_set_state(port, FR_SWAP_SEND, 0);
> -                       else
> +                       if (port->state == SNK_READY) {
> +                               int ret;
> +
> +                               port->upcoming_state = FR_SWAP_SEND;
> +                               ret = tcpm_ams_start(port, FAST_ROLE_SWAP);
> +                               if (ret == -EAGAIN)
> +                                       port->upcoming_state = INVALID_STATE;
> +                       } else {
>                                 tcpm_log(port, "Discarding FRS_SIGNAL!
> Not in sink ready");
> +                       }
>
> #2
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4449,9 +4449,14 @@ static void tcpm_enable_frs_work(struct
> kthread_work *work)
>         if (port->state != SNK_READY || port->vdm_state !=
> VDM_STATE_DONE || port->send_discover)
>                 goto resched;
>
> -       tcpm_set_state(port, GET_SINK_CAP, 0);
> -       port->sink_cap_done = true;
> -
> +       port->upcoming_state = GET_SINK_CAP;
> +       ret = tcpm_ams_start(port, GET_SINK_CAPABILITIES);
> +       if (ret == -EAGAIN) {
> +               port->upcoming_state = INVALID_STATE;
> +       } else {
> +               port->sink_cap_done = true;
> +               goto unlock;
> +       }
>
> Thanks,
> Badhri
>
>