From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FBE71993B9 for ; Fri, 13 Jun 2025 19:50:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749844220; cv=none; b=nfuL1BLtQdNDpol0CBJLQzl1+quR+V02zOhEMb0bcotN18PebYcbP5kDXjJFcBQk6ZcKmn2DEYmK8UfIohDwQmo+wIopa8RQ2ZlcdUWqsTBIGMWaG8Y8lwnmiyZbNi9M0umxwMp93OW8Vp6k0M8oQoK9ejhsN+VUSxSKr/CwUlw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749844220; c=relaxed/simple; bh=5TN1U9ebRpInQhlmxgrGngSVCzw7SPkA2gaMYEUjLqI=; h=From:To:Subject:Date:Message-ID:Content-Type:MIME-Version; b=BU6bM2duOLYfBogaNfuQeqmb1M0oHTtMnsniEjb+Iew1Y10stLhTlxo2I9WbXgyYwFrQqHM+WQPq9jHKLokhXDBLoqdeRQhvrTLURjQwqtidhEqLzht2sEg1i96fVSrFSpj7Jztcvm7xZl1wI1LgORWo4kOBrBOMh4OvKdtj9uQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Eugqr4Sw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Eugqr4Sw" Received: by smtp.kernel.org (Postfix) with ESMTPS id 01E8EC4CEE3 for ; Fri, 13 Jun 2025 19:50:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749844220; bh=5TN1U9ebRpInQhlmxgrGngSVCzw7SPkA2gaMYEUjLqI=; h=From:To:Subject:Date:From; b=Eugqr4SwF/6P/8NT1oDa0wltFvQv3BgxW+YT6L8IJAruXtdNQN63mbDCOnpO5Ukyh 8Sv1XMFLt7aJJQFZldRFMob9z3TIuUtvzaBy+SCfodPeybBgVPo/n7HTWVBd6iobxC TRAe/jAZiGXDoMTmX/0375eRAbf3Vju4OTq1jGU40huLZeJk8HbtWr36blhRXQnLvU nkcLgbZleo7aYE+dv5SIrvxgndxDSayaNj3TvuhCAUU65vpIYoerW6HH7ibpbQyIQ0 IJAsSeY4sNj1zcrR+t9HB0jbytMWYohoiRORfHMPvbVhsOWOPE/rS4kv5SEal2ekfy 756MtPuGEu/Mw== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id E622EC433E1; Fri, 13 Jun 2025 19:50:19 +0000 (UTC) From: bugzilla-daemon@kernel.org To: linux-usb@vger.kernel.org Subject: [Bug 220225] New: CH340 USB-serial converter wrong baud rate for 2400 and 1200 baud Date: Fri, 13 Jun 2025 19:50:19 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: AssignedTo drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Product: Drivers X-Bugzilla-Component: USB X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: pkk@spth.de X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter cf_regression Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D220225 Bug ID: 220225 Summary: CH340 USB-serial converter wrong baud rate for 2400 and 1200 baud Product: Drivers Version: 2.5 Hardware: All OS: Linux Status: NEW Severity: normal Priority: P3 Component: USB Assignee: drivers_usb@kernel-bugs.kernel.org Reporter: pkk@spth.de Regression: No I have a USB-serial converter (AFAIR I bought it as a CH340G years ago), wh= ere setting the baud rate to 2400 or 1200 results in it sending at 380 baud instead. The problem is the same for Linux 6.12.27 and FreeBSD 14.2. But the USB-serial converter works for OpenBSD 7.6. Linux dmesg when plugging it in: [450228.160661] usb 3-2: new full-speed USB device number 27 using xhci_hcd [450228.310942] usb 3-2: New USB device found, idVendor=3D1a86, idProduct= =3D7523, bcdDevice=3D 2.54 [450228.310957] usb 3-2: New USB device strings: Mfr=3D0, Product=3D2, SerialNumber=3D0 [450228.310964] usb 3-2: Product: USB2.0-Ser! [450228.316943] ch341 3-2:1.0: ch341-uart converter detected [450228.329674] ch341-uart ttyUSB3: break control not supported, using simulated break [450228.329889] usb 3-2: ch341-uart converter now attached to ttyUSB3 lsusb -v output on GNU/Linux: Bus 003 Device 027: ID 1a86:7523 QinHeng Electronics CH340 serial converter root@notebook6:~# lsusb -s 3:27 -v Bus 003 Device 027: ID 1a86:7523 QinHeng Electronics CH340 serial converter Negotiated speed: Full Speed (12Mbps) Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 255 Vendor Specific Class bDeviceSubClass 0 [unknown] bDeviceProtocol 0=20 bMaxPacketSize0 8 idVendor 0x1a86 QinHeng Electronics idProduct 0x7523 CH340 serial converter bcdDevice 2.54 iManufacturer 0=20 iProduct 2 USB2.0-Ser! iSerial 0=20 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0027 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0=20 bmAttributes 0x80 (Bus Powered) MaxPower 96mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 3 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 1 [unknown] bInterfaceProtocol 2=20 iInterface 0=20 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0008 1x 8 bytes bInterval 1 Device Status: 0x0000 (Bus Powered) Corresponding FreeBSD bug report: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D287509 --=20 You may reply to this email to add a comment. 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