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[23.128.96.18]) by mx.google.com with ESMTP id ca6si6043603edb.553.2021.08.18.07.24.26; Wed, 18 Aug 2021 07:24:51 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=e6oCACt8; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239379AbhHROXN (ORCPT + 99 others); Wed, 18 Aug 2021 10:23:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239637AbhHROWt (ORCPT ); Wed, 18 Aug 2021 10:22:49 -0400 Received: from mail-ot1-x336.google.com (mail-ot1-x336.google.com [IPv6:2607:f8b0:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAED6C061D73; Wed, 18 Aug 2021 07:17:04 -0700 (PDT) Received: by mail-ot1-x336.google.com with SMTP id m7-20020a9d4c87000000b0051875f56b95so3855951otf.6; Wed, 18 Aug 2021 07:17:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=MTrq4MWiD0jHz6dQsXwiM7un+x87SnGMy8PpS4ND41s=; b=e6oCACt8II/QhoyQTozoa8tX8Pe+dAkO+JriZGdWPMa8w73Zw2059Pq7uaZdmedMxP KFO5wjs5mxhl2rkUqGCHS3SA1XBUB6w2drABIkJUNCEGpr8IuJTLd5QHW91ZSu3nLJjH +VFblj84ZCZKDu6yih1neYbSUgdE1W6h3Wco25LM90ANtpZnOdHe5EhQN87e8fcUr0OA mZJSACqNUiifj+NTdEmBXD/bCoIi58eLFRhloKyY/55O87P5gAOr3TUi/ljAan9n96Sy D2RQlKpFTnHSWDKY6aUk97r83C4awjmK1F1AklcVzUGdgeemyuvvr5CuQY4DjCXGx71U j5pA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=MTrq4MWiD0jHz6dQsXwiM7un+x87SnGMy8PpS4ND41s=; b=mvXv3p6GRqLJ8hSetnhnjXK8q2j6Zknb0swFB/h2mvv3Vcte1eEEZRJoVVgT7EP2PJ hHu75uk9DQGvxt7otk5vOV+XLGDT6bLoqsm9VCiGhQe31e9gNYEeQKNyjFVLVgu+l2xh 1JiRlRz3R1WFWPPyXpUWeZM9wSJYIfjFwEpfLQ/zCc1fSJ6wxECrI855Q2iMF/BewkK3 fDCh1DRQSRIJ164IrHm8aLuqjWCXWrXB5w6FNe/aU8lYKdlazdBpnojiXu7P74g1vrp3 oa5UglvGbO9w+kMwOTOHIz/pWCInG7+bgYXa1m9OaLmwH0rV3tCE1prOIG8VA8VugEU3 Bukg== X-Gm-Message-State: AOAM530bYQVkofHAp6LuUizXUQQxB+RfthgybOGFnLE+Wy+6WM0RWscG Y4nAEjmmiofD3Z2AoRLpoHwDhRf5hwY= X-Received: by 2002:a05:6830:4102:: with SMTP id w2mr7349771ott.166.1629296223977; Wed, 18 Aug 2021 07:17:03 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id w16sm32218oih.19.2021.08.18.07.17.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Aug 2021 07:17:03 -0700 (PDT) Sender: Guenter Roeck Subject: Re: [PATCH] usb: typec: tcpm: Raise vdm_sm_running flag only when VDM SM is running To: Kyle Tso , heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org Cc: badhri@google.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210816075449.2236547-1-kyletso@google.com> From: Guenter Roeck Message-ID: <05b01a2e-b1ee-4111-2e3c-897990544c0a@roeck-us.net> Date: Wed, 18 Aug 2021 07:17:02 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210816075449.2236547-1-kyletso@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/16/21 12:54 AM, Kyle Tso wrote: > If the port is going to send Discover_Identity Message, vdm_sm_running > flag was intentionally set before entering Ready States in order to > avoid the conflict because the port and the port partner might start > AMS at almost the same time after entering Ready States. > > However, the original design has a problem. When the port is doing > DR_SWAP from Device to Host, it raises the flag. Later in the > tcpm_send_discover_work, the flag blocks the procedure of sending the > Discover_Identity and it might never be cleared until disconnection. > > Since there exists another flag send_discover representing that the port > is going to send Discover_Identity or not, it is enough to use that flag > to prevent the conflict. Also change the timing of the set/clear of > vdm_sm_running to indicate whether the VDM SM is actually running or > not. > > Fixes: c34e85fa69b9 ("usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work") > Cc: Badhri Jagan Sridharan > Signed-off-by: Kyle Tso Reviewed-by: Guenter Roeck > --- > drivers/usb/typec/tcpm/tcpm.c | 81 ++++++++++++++++------------------- > 1 file changed, 38 insertions(+), 43 deletions(-) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index 5b22a1c931a9..c05ddfbaff08 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -341,6 +341,7 @@ struct tcpm_port { > bool vbus_source; > bool vbus_charge; > > + /* Set to true when Discover_Identity Command is expected to be sent in Ready states. */ > bool send_discover; > bool op_vsafe5v; > > @@ -370,6 +371,7 @@ struct tcpm_port { > struct hrtimer send_discover_timer; > struct kthread_work send_discover_work; > bool state_machine_running; > + /* Set to true when VDM State Machine has following actions. */ > bool vdm_sm_running; > > struct completion tx_complete; > @@ -1431,6 +1433,7 @@ static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header, > /* Set ready, vdm state machine will actually send */ > port->vdm_retries = 0; > port->vdm_state = VDM_STATE_READY; > + port->vdm_sm_running = true; > > mod_vdm_delayed_work(port, 0); > } > @@ -1673,7 +1676,6 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev, > rlen = 1; > } else { > tcpm_register_partner_altmodes(port); > - port->vdm_sm_running = false; > } > break; > case CMD_ENTER_MODE: > @@ -1721,14 +1723,12 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev, > (VDO_SVDM_VERS(svdm_version)); > break; > } > - port->vdm_sm_running = false; > break; > default: > response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK); > rlen = 1; > response[0] = (response[0] & ~VDO_SVDM_VERS_MASK) | > (VDO_SVDM_VERS(svdm_version)); > - port->vdm_sm_running = false; > break; > } > > @@ -1765,6 +1765,20 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port, > } > > if (PD_VDO_SVDM(p[0])) { > + /* > + * Here a SVDM is received (INIT or RSP or unknown). Set the vdm_sm_running in > + * advance because we are dropping the lock but may send VDMs soon. > + * For the cases of INIT received: > + * - If no response to send, it will be cleared later in this function. > + * - If there are responses to send, it will be cleared in the state machine. > + * For the cases of RSP received: > + * - If no further INIT to send, it will be cleared later in this function. > + * - Otherwise, it will be cleared in the state machine if timeout or it will go > + * back here until no further INIT to send. > + * For the cases of unknown type received: > + * - We will send NAK and the flag will be cleared in the state machine. > + */ > + port->vdm_sm_running = true; > rlen = tcpm_pd_svdm(port, adev, p, cnt, response, &adev_action); > } else { > if (port->negotiated_rev >= PD_REV30) > @@ -1833,6 +1847,8 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port, > > if (rlen > 0) > tcpm_queue_vdm(port, response[0], &response[1], rlen - 1); > + else > + port->vdm_sm_running = false; > } > > static void tcpm_send_vdm(struct tcpm_port *port, u32 vid, int cmd, > @@ -1898,8 +1914,10 @@ static void vdm_run_state_machine(struct tcpm_port *port) > * if there's traffic or we're not in PDO ready state don't send > * a VDM. > */ > - if (port->state != SRC_READY && port->state != SNK_READY) > + if (port->state != SRC_READY && port->state != SNK_READY) { > + port->vdm_sm_running = false; > break; > + } > > /* TODO: AMS operation for Unstructured VDM */ > if (PD_VDO_SVDM(vdo_hdr) && PD_VDO_CMDT(vdo_hdr) == CMDT_INIT) { > @@ -2555,10 +2573,6 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, > TYPEC_PWR_MODE_PD, > port->pps_data.active, > port->supply_voltage); > - /* Set VDM running flag ASAP */ > - if (port->data_role == TYPEC_HOST && > - port->send_discover) > - port->vdm_sm_running = true; > tcpm_set_state(port, SNK_READY, 0); > } else { > /* > @@ -2596,14 +2610,10 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, > switch (port->state) { > case SNK_NEGOTIATE_CAPABILITIES: > /* USB PD specification, Figure 8-43 */ > - if (port->explicit_contract) { > + if (port->explicit_contract) > next_state = SNK_READY; > - if (port->data_role == TYPEC_HOST && > - port->send_discover) > - port->vdm_sm_running = true; > - } else { > + else > next_state = SNK_WAIT_CAPABILITIES; > - } > > /* Threshold was relaxed before sending Request. Restore it back. */ > tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_PD, > @@ -2618,10 +2628,6 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, > port->pps_status = (type == PD_CTRL_WAIT ? > -EAGAIN : -EOPNOTSUPP); > > - if (port->data_role == TYPEC_HOST && > - port->send_discover) > - port->vdm_sm_running = true; > - > /* Threshold was relaxed before sending Request. Restore it back. */ > tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_PD, > port->pps_data.active, > @@ -2697,10 +2703,6 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, > } > break; > case DR_SWAP_SEND: > - if (port->data_role == TYPEC_DEVICE && > - port->send_discover) > - port->vdm_sm_running = true; > - > tcpm_set_state(port, DR_SWAP_CHANGE_DR, 0); > break; > case PR_SWAP_SEND: > @@ -2738,7 +2740,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, > PD_MSG_CTRL_NOT_SUPP, > NONE_AMS); > } else { > - if (port->vdm_sm_running) { > + if (port->send_discover) { > tcpm_queue_message(port, PD_MSG_CTRL_WAIT); > break; > } > @@ -2754,7 +2756,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, > PD_MSG_CTRL_NOT_SUPP, > NONE_AMS); > } else { > - if (port->vdm_sm_running) { > + if (port->send_discover) { > tcpm_queue_message(port, PD_MSG_CTRL_WAIT); > break; > } > @@ -2763,7 +2765,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port, > } > break; > case PD_CTRL_VCONN_SWAP: > - if (port->vdm_sm_running) { > + if (port->send_discover) { > tcpm_queue_message(port, PD_MSG_CTRL_WAIT); > break; > } > @@ -4479,18 +4481,20 @@ static void run_state_machine(struct tcpm_port *port) > /* DR_Swap states */ > case DR_SWAP_SEND: > tcpm_pd_send_control(port, PD_CTRL_DR_SWAP); > + if (port->data_role == TYPEC_DEVICE || port->negotiated_rev > PD_REV20) > + port->send_discover = true; > tcpm_set_state_cond(port, DR_SWAP_SEND_TIMEOUT, > PD_T_SENDER_RESPONSE); > break; > case DR_SWAP_ACCEPT: > tcpm_pd_send_control(port, PD_CTRL_ACCEPT); > - /* Set VDM state machine running flag ASAP */ > - if (port->data_role == TYPEC_DEVICE && port->send_discover) > - port->vdm_sm_running = true; > + if (port->data_role == TYPEC_DEVICE || port->negotiated_rev > PD_REV20) > + port->send_discover = true; > tcpm_set_state_cond(port, DR_SWAP_CHANGE_DR, 0); > break; > case DR_SWAP_SEND_TIMEOUT: > tcpm_swap_complete(port, -ETIMEDOUT); > + port->send_discover = false; > tcpm_ams_finish(port); > tcpm_set_state(port, ready_state(port), 0); > break; > @@ -4502,7 +4506,6 @@ static void run_state_machine(struct tcpm_port *port) > } else { > tcpm_set_roles(port, true, port->pwr_role, > TYPEC_HOST); > - port->send_discover = true; > } > tcpm_ams_finish(port); > tcpm_set_state(port, ready_state(port), 0); > @@ -4645,8 +4648,6 @@ static void run_state_machine(struct tcpm_port *port) > break; > case VCONN_SWAP_SEND_TIMEOUT: > tcpm_swap_complete(port, -ETIMEDOUT); > - if (port->data_role == TYPEC_HOST && port->send_discover) > - port->vdm_sm_running = true; > tcpm_set_state(port, ready_state(port), 0); > break; > case VCONN_SWAP_START: > @@ -4662,14 +4663,10 @@ static void run_state_machine(struct tcpm_port *port) > case VCONN_SWAP_TURN_ON_VCONN: > tcpm_set_vconn(port, true); > tcpm_pd_send_control(port, PD_CTRL_PS_RDY); > - if (port->data_role == TYPEC_HOST && port->send_discover) > - port->vdm_sm_running = true; > tcpm_set_state(port, ready_state(port), 0); > break; > case VCONN_SWAP_TURN_OFF_VCONN: > tcpm_set_vconn(port, false); > - if (port->data_role == TYPEC_HOST && port->send_discover) > - port->vdm_sm_running = true; > tcpm_set_state(port, ready_state(port), 0); > break; > > @@ -4677,8 +4674,6 @@ static void run_state_machine(struct tcpm_port *port) > case PR_SWAP_CANCEL: > case VCONN_SWAP_CANCEL: > tcpm_swap_complete(port, port->swap_status); > - if (port->data_role == TYPEC_HOST && port->send_discover) > - port->vdm_sm_running = true; > if (port->pwr_role == TYPEC_SOURCE) > tcpm_set_state(port, SRC_READY, 0); > else > @@ -5028,9 +5023,6 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port) > switch (port->state) { > case SNK_TRANSITION_SINK_VBUS: > port->explicit_contract = true; > - /* Set the VDM flag ASAP */ > - if (port->data_role == TYPEC_HOST && port->send_discover) > - port->vdm_sm_running = true; > tcpm_set_state(port, SNK_READY, 0); > break; > case SNK_DISCOVERY: > @@ -5425,15 +5417,18 @@ static void tcpm_send_discover_work(struct kthread_work *work) > if (!port->send_discover) > goto unlock; > > + if (port->data_role == TYPEC_DEVICE && port->negotiated_rev < PD_REV30) { > + port->send_discover = false; > + goto unlock; > + } > + > /* Retry if the port is not idle */ > if ((port->state != SRC_READY && port->state != SNK_READY) || port->vdm_sm_running) { > mod_send_discover_delayed_work(port, SEND_DISCOVER_RETRY_MS); > goto unlock; > } > > - /* Only send the Message if the port is host for PD rev2.0 */ > - if (port->data_role == TYPEC_HOST || port->negotiated_rev > PD_REV20) > - tcpm_send_vdm(port, USB_SID_PD, CMD_DISCOVER_IDENT, NULL, 0); > + tcpm_send_vdm(port, USB_SID_PD, CMD_DISCOVER_IDENT, NULL, 0); > > unlock: > mutex_unlock(&port->lock); >