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From: Paul Fulghum <paulkf@microgate.com>
To: Thomas Stewart <thomas@stewarts.org.uk>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: belkin usb serial converter (mct_u232), break not working
Date: Wed, 20 Oct 2004 17:27:08 -0500	[thread overview]
Message-ID: <1098311228.6006.3.camel@at2.pipehead.org> (raw)
In-Reply-To: <200410202308.02624.thomas@stewarts.org.uk>

On Wed, 2004-10-20 at 17:08, Thomas Stewart wrote:

> take porttest.c:
> #include <sys/fcntl.h>
> #include <sys/ioctl.h>
> main(int argc, char ** argv) {
>         int fd = open(argv[1], O_RDWR|O_NOCTTY);
>         ioctl(fd, TCSBRKP, 20);
>         close(fd);
> }
> 
> $ time ./porttest /dev/ttyS0
> real    0m2.001s
> user    0m0.001s
> sys     0m0.000s
> 
> A standard serial port with a 2 second break (20*100ms), takes as expected 
> just over 2 seconds.
> 
> $ time ./porttest /dev/ttyUSB1
> real    0m0.004s
> user    0m0.000s
> sys     0m0.001s
> 
> However with the USB converter instead, it takes 5 ms to complete. Much 
> shorter than expected.
> 
> Is it a driver issue?

Can you record and display the return code from the ioctl()?

Thanks

-- 
Paul Fulghum
paulkf@microgate.com



  parent reply	other threads:[~2004-10-20 22:59 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-20 18:46 belkin usb serial converter (mct_u232), break not working Thomas Stewart
2004-10-20 20:48 ` Paul Fulghum
2004-10-20 21:22 ` Paul Fulghum
2004-10-20 22:08   ` Thomas Stewart
2004-10-20 22:15     ` Paul Fulghum
2004-10-20 22:21     ` Paul Fulghum
2004-10-20 22:27     ` Paul Fulghum [this message]
2004-10-20 23:04       ` Thomas Stewart
2004-10-21  2:37         ` Paul Fulghum
2004-10-21 10:06           ` Thomas Stewart
2004-10-21 12:41             ` Paul Fulghum
2004-10-21 19:44               ` Paul Fulghum
2004-11-04 18:20                 ` Thomas Stewart
2004-11-04 19:21                   ` Paul Fulghum

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