From: Johan Hovold <johan@kernel.org>
To: Helge Deller <deller@gmx.de>
Cc: Johan Hovold <johan@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] USB: serial: ftdi_sio: Fix serial port stall after resume
Date: Wed, 28 Oct 2020 16:01:05 +0100 [thread overview]
Message-ID: <20201028150105.GJ4085@localhost> (raw)
In-Reply-To: <a2b84135-761b-6e9c-59d5-857bfa6d0281@gmx.de>
On Wed, Oct 28, 2020 at 03:54:35PM +0100, Helge Deller wrote:
> On 10/27/20 10:00 AM, Johan Hovold wrote:
> > On Thu, Oct 08, 2020 at 08:16:02PM +0200, Helge Deller wrote:
> >> My testcase is pretty simple:
> >> 1. I use e.g. "minicom -D /dev/ttyUSB2". Serial connection works.
> >> 2. I exit minicom.
> >> 3. I suspend the workstation: "systemctl suspend"
> >> 4. I wake up the machine and wait a few seconds.
> >> 5. I start "minicom -D /dev/ttyUSB2" again. No transfers on the serial port.
> >>
> >> With my patch the minicom serial communications does work.
> >> Another way to wake up the connection is to rmmod the driver and
> >> insmod it again.
> >
> > Weird indeed. If you exit minicom before suspend and no other process is
> > keeping the port open, then that write_latency_timer() above would never
> > be executed.
> >
> > Could you enable some debugging and provide a dmesg log from a test
> > cycle (open/close minicom, suspend/resume, open minicom)?
> >
> > echo file usb-serial.c +p > /sys/kernel/debug/dynamic_debug/control
>
> I enabled the debugging and tried a few times, but somehow I can not
> reproduce the issue any longer.
>
> So, please drop my patch for now.
Good to hear the problem's gone. :) Let us know if you run into it
again.
Johan
prev parent reply other threads:[~2020-10-29 2:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 19:33 [PATCH] USB: serial: ftdi_sio: Fix serial port stall after resume Helge Deller
2020-10-08 15:21 ` Johan Hovold
2020-10-08 18:16 ` Helge Deller
2020-10-27 9:00 ` Johan Hovold
2020-10-28 14:54 ` Helge Deller
2020-10-28 15:01 ` Johan Hovold [this message]
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