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
next prev 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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