Bug#867365: 8250_moxa: interferes with hardware
Source: linux
Severity: normal
Dear Maintainer,
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From: root <root@gavbuntu>
To: Debian Bug Tracking System <submit@bugs.debian.org>
Subject: 8250_moxa: driver causes hardware fault
Message-ID: <149930682178.1976.1310054348253285119.reportbug@nexusnpu>
X-Mailer: reportbug 7.1.7
Date: Thu, 06 Jul 2017 02:07:01 +0000
Source: linux
Version: 4.9.30-2+deb9u2
Severity: normal
Dear Maintainer,
After upgrading to this kernel version, my Moxa CP-132EL serial card no longer works correctly.
Specifically, when an application requested a baud rate of 115200, the baud rate actually used was 123600 (or thereabouts), and when requesting a baud rate of 921600, the baud rate actually used was 1000000 (which this card isn't supposed to even be capable of).
I am using the official vendor driver for this card, via a DKMS wrapper package that I wrote myself. The wrapper can be found at https://github.com/uecasm/mxser.git (and a link to the vendor code can be found there too).
It appears that even loading the 8250_moxa driver causes the fault -- if it is loaded at boot, then I rmmod it and modprobe the mxupcie vendor driver, the fault remains.
(Trying to use the 8250_moxa driver by itself does not work; while it recognises the hardware it does not appear to communicate at any baud rate.)
I can work around the problem by blacklisting the 8250_moxa driver.
The problem also does not occur with linux-image-4.9.0-2-amd64 (4.9.13-1 2017-02-27), which is the kernel I had been using prior to this -- it appears that the 8250_moxa driver was disabled in that configuration.
So it appears this driver is faulty and I would suggest disabling it again.
-- System Information:
Debian Release: 9.0
APT prefers testing
APT policy: (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-3-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_NZ.UTF-8, LC_CTYPE=en_NZ.UTF-8 (charmap=UTF-8), LANGUAGE=en_NZ.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
-- System Information:
Debian Release: 9.0
APT prefers testing
APT policy: (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-3-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_NZ.UTF-8, LC_CTYPE=en_NZ.UTF-8 (charmap=UTF-8), LANGUAGE=en_NZ.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
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