From: Jiri Slaby <jslaby@suse.cz>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Jiri Slaby <jirislaby@gmail.com>
Subject: Re: serial ports now asserting DTR and RTS during boot; breaks connected hardware
Date: Wed, 04 Jan 2012 21:54:29 +0100 [thread overview]
Message-ID: <4F04BC85.9060803@suse.cz> (raw)
In-Reply-To: <20120103160655.69107c93@pyramind.ukuu.org.uk>
On 01/03/2012 05:06 PM, Alan Cox wrote:
> On Tue, 3 Jan 2012 10:37:07 -0500
> Dave Jones <davej@redhat.com> wrote:
>
>> Jiri,
>> We got this report from a user who notes a change in behaviour for
>> his serial hardware over the last few kernel versions.
>>
>> https://bugzilla.redhat.com/show_bug.cgi?id=771010
>>
>> This sounds like it might be related to your DTR/RTS changes back in March 2011 maybe ?
>
> Looks like your userspace to me at first glance.
>
> ftdi_sio sets up the modem lines in set_termios. Set_termios is called
> from ftdi_open. ftdi_open is triggered by userspace.
>
>> > The following code in the ftdi_sio driver is one suspect but this behavior
>> > happens on 8250 UARTs also so it is systemic now,
>
> Likewise 8250 sets up the lines in serial8250_startup. This is called via
> uart_startup which is called via open.
Ok, let's apply the cut&paste rule. Does uninstalling ModemManager fix
the issue?
--
js
suse labs
next prev parent reply other threads:[~2012-01-04 20:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-03 15:37 serial ports now asserting DTR and RTS during boot; breaks connected hardware Dave Jones
2012-01-03 16:00 ` Jiri Slaby
2012-01-03 16:13 ` Dave Jones
2012-01-04 18:43 ` Jiri Slaby
2012-01-03 16:06 ` Alan Cox
2012-01-04 20:54 ` Jiri Slaby [this message]
2012-01-04 22:37 ` Chris Elmquist
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