From: Johan Hovold <johan@kernel.org>
To: bugzilla-daemon@bugzilla.kernel.org
Cc: linux-usb@vger.kernel.org
Subject: Re: [Bug 208959] New: USB-serial (mct_u232): bit7=1 when tty is set to cs7?
Date: Mon, 24 Aug 2020 10:42:14 +0200 [thread overview]
Message-ID: <20200824084214.GA21288@localhost> (raw)
In-Reply-To: <bug-208959-208809@https.bugzilla.kernel.org/>
On Wed, Aug 19, 2020 at 02:52:47AM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=208959
>
> Bug ID: 208959
> Summary: USB-serial (mct_u232): bit7=1 when tty is set to cs7?
> Product: Drivers
> Version: 2.5
> Kernel Version: 5.7.0
> Hardware: All
> OS: Linux
> Tree: Mainline
> Status: NEW
> Severity: low
> Priority: P1
> Component: USB
> Assignee: drivers_usb@kernel-bugs.kernel.org
> Reporter: mslade@epic-code.com.au
> Regression: No
>
> I'm not 100% certain this is a bug, please let me know if this is expected
> behavior.
>
> I have hooked an old serial mouse up to a USB serial device, USB ID 0711:0230
> (part of an circa 2000 Targus port replicator)
>
> when I configure it with the appropriate 1200 baud and 7 bit char width, the
> bytes that come through /dev/ttyUSB0 all have bit7 set to 1.
>
> This behavior is in contrast to an old serial port on a box running a 2.4.19
> kernel.
>
> Is there a standard for the value that non-data bits should be set to?
This sounds like a configuration issue. If the mouse is indeed using
7n1 and the converter is expecting 8n1 you could end up with bit 7
always set on input.
Can you verify that the converter is configured correctly, for example,
by reading out the termios settings, enabling debugging and/or
connecting it to another serial port configured for 7n1?
Johan
next prev parent reply other threads:[~2020-08-24 9:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 2:52 [Bug 208959] New: USB-serial (mct_u232): bit7=1 when tty is set to cs7? bugzilla-daemon
2020-08-24 8:42 ` Johan Hovold [this message]
2020-08-24 8:42 ` [Bug 208959] " bugzilla-daemon
2020-08-25 15:20 ` bugzilla-daemon
2020-08-26 7:08 ` Johan Hovold
2020-08-26 7:08 ` bugzilla-daemon
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