Greg KH said the following on 03/16/10 01:54:
On Sun, Mar 14, 2010 at 12:18:16PM +1100, Bernardo wrote:
Greg KH said the following on 03/14/10 02:16:
On Sat, Mar 13, 2010 at 02:23:17PM +1100, Bernardo wrote:
I'm working on an embedded device which our customers can configure (and
run some diagnostics) using serial port. The new version of the
device has an USB port instead and there is an issue how to let
the customers
use it to perform configuration in a similar fashion. BTW the
customers, for all practical purposes, *always* run Windows on
their PCs.
After a bit of searching the net an obvious solution was to use the
gadget serial module. That worked -- to a degree. When the host was
running GNU/Linux everything was fine. However when the host was running
Windows (XP) the comms would lock up after a while, usually a
few minutes but sometimes in less than a minute. To get the
comms working again we needed to disable/enable the USB port on
the host side and restart the application on the device, not
something that would be acceptable.
Is the lockup happening on the device side, or on the host side? If
it's on the device, we would have a chance to fix this up. This should
work properly, as lots of people use it like you are wanting to. I
would recommend working through this to try to solve the issues as it
seems you are almost there.
greg k-h
Hi Greg,
My impression was that the host side was seizing up. Don't remember
seeing anything unusual in /var/log/messages on the device but will
double check it when back at work.
Also, g_serial never had to be unloaded/loaded again to get things
back to normal, when i tried doing that - it made no difference. But
on the host side i did have to disable/re-enable the USB port to get
the comms going again. Given that with a Linux host everything was
working just fine it seemed like the Windows driver was flaky.
This wouldn't be the first time that people have reported that windows
driver as having issues. I suggest filing a bug with Microsoft about
it.
will check with the guys in office, i think some of them have already
filed other bug reports with MS - although i won't be holding my breath
waiting for a fix
Initially I didn't want to unnecessarily confuse the issue but there
is a bit more to the story and it may be worth mentioning; our
application (on the device side) is a multi threaded one where a
separate thread is reading/writing to the port; when it was replaced
with a bare bone test program that just reads from USB port and
echoes lines back (literally less than 10 lines of code) I didn't
see any lockups. This was puzzling but I'd really need to write a
test program on the host side, pumping more input to confirm there
is indeed no lockup. I was just using Hyperterminal (and TeraTerm
too, made no difference) for quick testing.
I don't know much, if anything, we can do about this on the Linux side,
sorry. It looks like you need to contact Microsoft and work with them
on resolving this issue.
good luck,
greg k-h
i was poking around and got the "Ethernet over USB" (RNDIS) mode
working, with a very simple Python script on the host side
sending/receiving UDP packets; the first iteration looks very promising
still, it would be nice to have the serial version working; i'll report
back if there is any news on that front
--
Thanks, Bernardo
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