Date: Sat, 08 Jan 2005 11:38:23 -0800 From: Brandon Fosdick <bfoz@bfoz.net> To: "M. Warner Losh" <imp@bsdimp.com> Cc: freebsd-stable@freebsd.org Subject: Re: ucom and sio Message-ID: <41E036AF.2030407@bfoz.net> In-Reply-To: <20050102.220156.79545944.imp@bsdimp.com> References: <40170.4.248.235.201.1104333403.squirrel@4.248.235.201> <20050102.220156.79545944.imp@bsdimp.com>
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M. Warner Losh wrote:
> In message: <40170.4.248.235.201.1104333403.squirrel@4.248.235.201>
> "Brandon Fosdick" <bfoz@bfoz.net> writes:
> : Judging from the man page, ucom is limited to acting like a tty with no
> : support for sio. Is this true? Is there some magic config bit somewhere
> : that will enable hidden sio support?
>
> Ummm, I don't know what you are asking here. ucom supports all the
> rs232 stuff w/o problem. I use it all the time with my phone to dial
> into the network.
Well, then I must be doing something wrong. The man page for ucom would
seem to indicate that it is tty only...
"The ucom driver attaches to USB modems, serial ports, and other
devices that need to look like a tty. The ucom driver shows a behavior
like a tty(4). This means that normal programs such as tip(1) or
pppd(8) can be used to access the device."
If I use tip it works fine. But if I try to write a C program that opens
the device it hangs on open, unless I set it to non-blocking. Then open
returns and I set it back to blocking then try a read or a write. read()
blocks regardless of whether any data has been sent by the other device
(a terminal app on my palm pilot for debugging purposes) and write()
blocks without sending anything. If I set the device to be non-blocking
read() will return the data that was sent by the other device, but
write() will still block.
Oddly, I get the same behavior on my powerbook, so I thought the adapter
was defective. But it works with terminal apps on freebsd, osx and
windows, so I'm pretty sure its working. I have no idea what I'm doing
wrong though. Once I figure out where I put the code for this thing I'll
send the test program I've been using. I always seem to lose something
when I travel...
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