From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f182.google.com (mail-qt1-f182.google.com [209.85.160.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98C2337880B for ; Thu, 2 Apr 2026 18:30:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775154603; cv=none; b=aszp2pETAKBflZz3cXq2P5K3M1kAo3UKEgKZfQdWYfmBazqgi3jT+mnS43uKuOwQ6LKw9+hcBbpDJkprYgLRJBzQ/rYtXYYMInDFP+xNk2treaefMkjy6wFIIljX2xopb3LozEC8PlNiugCkGU5GKtNyhVmMaiGvgZfTmkMD+AY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775154603; c=relaxed/simple; bh=DvqNfMAlcitmhGBcbtnBF01Zx2ZcpE4CrNZVy68rm4E=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=SqThkfBhJ0SGtER7jVSZYNWmjZgwbGXD0h5O5rKwyZpF6MVKLvWV90s4BzzCYlNhMXCRCpc8otiY7hYKI9r8PyZ31YSh+INn7khCWumnulC9tlmUztS2iNGavg8VhZSpFc9t6bI8Z3uuFmmQ7dw2VnBExmeuHcWPBXaNBbzADPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=jj76FLMP; arc=none smtp.client-ip=209.85.160.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jj76FLMP" Received: by mail-qt1-f182.google.com with SMTP id d75a77b69052e-506a747448dso9390971cf.0 for ; Thu, 02 Apr 2026 11:30:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1775154600; x=1775759400; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=dLel0edgFVWLHzeO67CzLVLJkUJgZaH6amipswMrBIQ=; b=jj76FLMPj5ALsMMp42jH4nuNp8t7/idvJeQcAE9hqnvE8kFnu+xKCVbP7Ry8F2mmRy 1fTtj0oLWBIprba51eJ6ZVT8LMCqsfkf3oYuBgDt0lsonZ4BA4srL2gLtjUUC0axuJUC 9bHusvwpLMJmDPMwVl3U3ie3IcLF6G3N9OSEJHRX7doFm+vup67u1/i/8eIwT3SqQVeb /yg/pTBIt/HnL7/MYNkdIdCdoOJulWdZKXEE997XP1RNo9FdOIMuk4ZjgeuNbzk/svQ7 Pp5E5qZPEbLyCr3Ghtc6k0d/2G3k1iVzxZDE6MiIv9KQVqlsrHZ1wMQWNFZ5IYUTYJQT QIlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775154600; x=1775759400; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=dLel0edgFVWLHzeO67CzLVLJkUJgZaH6amipswMrBIQ=; b=mYxKh8tYAh2nyjt8D/Cm6IfxM5eTEb7jQznSYnAQyCZrRF0UNcOhwK7sevRZxu8DL6 WBl8QTvnGFwQpmqfLXDkAe0NngeaPC8EAPw5gUorod8KULxMjsSH2lAHXlAn3MDUC6jh 2pAw11G0Qfe1BAPHhVa671kQW6NrU5Ilf2R7XOfWSYlR9tDkn+d2dpfmJv1QsCocokCd WLMRfXA9/yh/+XOVJTlZQeFn1+iQGdOhWZWspSFR0hb7bubAKQCpNwUzzjdmtidyZb+n 6jVEYC7Z51AsVWX2yo+6rpIMZeSCLHbBjeQZPfMopz0LGyQtQsjFOi++yPZ1POvLh3JZ O8OQ== X-Forwarded-Encrypted: i=1; AJvYcCV5ml+G8/65Mw1DpPahE1vFQHZ9MbbIWcAgYvhG1PZqhNXjndZM8vUa+Jm2FwKQplEAcC257X4iUyPoWMc=@vger.kernel.org X-Gm-Message-State: AOJu0Yzo/sgv9PUrOKFX1k/+s+1Mpo+Nq4DCyohUeH4wdsDg+KJQo92j /79SpUFZqG5Ab9HeK+PztCPk6lTJbVK05S+bJTiUVVNptKu+8cA9op+0 X-Gm-Gg: ATEYQzwp03PwY25VWSF7CV1DS7wLK5FcikxVz19O2A6kh6Wi8dJ6sidqiMDZIpU0VwK t6rzQKCu/fNpwnSrkKJgr8DlPyEgoZwlZtX6pY3ykId1VsC5MYkGmLHkb7T9h9rIz7AHuqSYIee NKvzymRvPsscMh/PWLMqeo8zPYXSaN8jcpmf55YWMCLmbYpqGfqeHzQoli8InF1TBvm3Bx0fTWf gkNr3QBpqhyXibq2rdu14rZhsATCDpmSHnU5IKWpYrTGiobBZr5gJ53PG9IsSnNnZbBXrl0/a2T hURK712RUdjPb2azFGLOj/Nit1+uZBWXoLRACxmtvco921qsmgh338+tDDIaZyc8iB+9fBbzPba 0K6CXzPsJN4Wl2BUxnETjOTAS5hJjLSUUBtPxPyyLi3U/u10wcU8xkPfqzOpCNm4f+TflQaoz5y rT1D6PKyO3a6s4Xs28jACg X-Received: by 2002:a05:622a:11c4:b0:509:e68:22de with SMTP id d75a77b69052e-50d62a70514mr6135601cf.32.1775154600463; Thu, 02 Apr 2026 11:30:00 -0700 (PDT) Received: from fedora ([2600:382:6114:1b06:cf32:7ce8:f756:4daf]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8a5977dac0esm27904286d6.46.2026.04.02.11.29.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Apr 2026 11:30:00 -0700 (PDT) From: Dave Carey To: oneukum@suse.com Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Dave Carey Subject: [PATCH] USB: cdc-acm: Add quirks for Yoga Book 9 14IAH10 INGENIC touchscreen Date: Thu, 2 Apr 2026 14:29:50 -0400 Message-ID: <20260402182950.389016-1-carvsdriver@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The Lenovo Yoga Book 9 14IAH10 (83KJ) has a composite USB device (17EF:6161) that controls both touchscreens via a CDC ACM interface. Interface 0 is a standard CDC ACM control interface, but interface 1 (the data interface) incorrectly declares vendor-specific class (0xFF) instead of USB_CLASS_CDC_DATA. cdc-acm rejects the device at probe with -EINVAL, leaving interface 0 unbound and EP 0x82 never polled. With no consumer polling EP 0x82, the firmware's watchdog fires every ~20 seconds and resets the USB bus, producing a continuous disconnect/ reconnect loop that prevents the touchscreens from ever initialising. Add two new quirk flags: VENDOR_CLASS_DATA_IFACE: Bypasses the bInterfaceClass check in acm_probe() that would otherwise reject the vendor-class data interface with -EINVAL. ALWAYS_POLL_CTRL: Submits the notification URB at probe() rather than waiting for a TTY open. This keeps EP 0x82 polled at all times, permanently suppressing the firmware watchdog. The URB is resubmitted after port_shutdown() and on system resume. SET_CONTROL_LINE_STATE (DTR|RTS) is sent at probe and after port_shutdown() to complete firmware handshake. Note: the firmware performs exactly 4 USB connect/disconnect cycles (~19 s each) on every cold boot before stabilising. This is a fixed firmware property; touch is available ~75-80 s after power-on. Signed-off-by: Dave Carey Tested-by: Dave Carey --- drivers/usb/class/cdc-acm.c | 53 ++++++++++++++++++++++++++++++++----- 1 file changed, 46 insertions(+), 7 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 7ede29d4c..568f0c479 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -114,6 +114,8 @@ static int acm_ctrl_msg(struct acm *acm, int request, int value, int retval; retval = usb_autopm_get_interface(acm->control); +#define VENDOR_CLASS_DATA_IFACE BIT(9) /* data interface uses vendor-specific class */ +#define ALWAYS_POLL_CTRL BIT(10) /* keep ctrl URB active even without an open TTY */ if (retval) return retval; @@ -710,12 +712,14 @@ static int acm_port_activate(struct tty_port *port, struct tty_struct *tty) set_bit(TTY_NO_WRITE_SPLIT, &tty->flags); acm->control->needs_remote_wakeup = 1; - acm->ctrlurb->dev = acm->dev; - retval = usb_submit_urb(acm->ctrlurb, GFP_KERNEL); - if (retval) { - dev_err(&acm->control->dev, - "%s - usb_submit_urb(ctrl irq) failed\n", __func__); - goto error_submit_urb; + if (!(acm->quirks & ALWAYS_POLL_CTRL)) { + acm->ctrlurb->dev = acm->dev; + retval = usb_submit_urb(acm->ctrlurb, GFP_KERNEL); + if (retval) { + dev_err(&acm->control->dev, + "%s - usb_submit_urb(ctrl irq) failed\n", __func__); + goto error_submit_urb; + } } acm_tty_set_termios(tty, NULL); @@ -788,6 +792,14 @@ static void acm_port_shutdown(struct tty_port *port) acm_unpoison_urbs(acm); + if (acm->quirks & ALWAYS_POLL_CTRL) { + acm->ctrlurb->dev = acm->dev; + if (usb_submit_urb(acm->ctrlurb, GFP_KERNEL)) + dev_dbg(&acm->control->dev, + "ctrl polling restart failed after port close\n"); + /* port_shutdown() cleared DTR/RTS; restore them */ + acm_set_control(acm, USB_CDC_CTRL_DTR | USB_CDC_CTRL_RTS); + } } static void acm_tty_cleanup(struct tty_struct *tty) @@ -1322,6 +1334,9 @@ static int acm_probe(struct usb_interface *intf, dev_dbg(&intf->dev, "Your device has switched interfaces.\n"); swap(control_interface, data_interface); + } else if (quirks & VENDOR_CLASS_DATA_IFACE) { + dev_dbg(&intf->dev, + "Vendor-specific data interface class, continuing.\n"); } else { return -EINVAL; } @@ -1516,6 +1531,9 @@ static int acm_probe(struct usb_interface *intf, acm->line.bDataBits = 8; acm_set_line(acm, &acm->line); + if (quirks & ALWAYS_POLL_CTRL) + acm_set_control(acm, USB_CDC_CTRL_DTR | USB_CDC_CTRL_RTS); + if (!acm->combined_interfaces) { rv = usb_driver_claim_interface(&acm_driver, data_interface, acm); if (rv) @@ -1537,6 +1555,13 @@ static int acm_probe(struct usb_interface *intf, dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor); + if (acm->quirks & ALWAYS_POLL_CTRL) { + acm->ctrlurb->dev = acm->dev; + if (usb_submit_urb(acm->ctrlurb, GFP_KERNEL)) + dev_warn(&intf->dev, + "failed to start persistent ctrl polling\n"); + } + return 0; err_release_data_interface: @@ -1663,7 +1688,7 @@ static int acm_resume(struct usb_interface *intf) acm_unpoison_urbs(acm); - if (tty_port_initialized(&acm->port)) { + if (tty_port_initialized(&acm->port) || (acm->quirks & ALWAYS_POLL_CTRL)) { rv = usb_submit_urb(acm->ctrlurb, GFP_ATOMIC); for (;;) { @@ -2007,6 +2032,20 @@ static const struct usb_device_id acm_ids[] = { /* CH343 supports CAP_BRK, but doesn't advertise it */ { USB_DEVICE(0x1a86, 0x55d3), .driver_info = MISSING_CAP_BRK, }, + /* + * Lenovo Yoga Book 9 14IAH10 (83KJ) — INGENIC 17EF:6161 touchscreen + * composite device. The CDC ACM control interface (0) uses a standard + * Union descriptor, but the data interface (1) is declared as vendor- + * specific class (0xff) with no CDC data descriptors, so cdc-acm would + * normally reject it. The firmware also requires continuous polling of + * the notification endpoint (EP 0x82) to suppress a 20-second watchdog + * reset; ALWAYS_POLL_CTRL keeps the ctrlurb active even when no TTY is + * open. Match only the control interface by class to avoid probing the + * vendor-specific data interface. + */ + { USB_DEVICE_INTERFACE_CLASS(0x17ef, 0x6161, USB_CLASS_COMM), + .driver_info = VENDOR_CLASS_DATA_IFACE | ALWAYS_POLL_CTRL }, + /* control interfaces without any protocol set */ { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, USB_CDC_PROTO_NONE) }, -- 2.53.0