From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <38EFCCD9.6263E7F9@denise.shiny.it> Date: Sat, 08 Apr 2000 20:20:41 -0400 From: Giuliano Pochini MIME-Version: 1.0 To: DeRobertis CC: linuxppc-dev@lists.linuxppc.org Subject: Re: stty crtscts < /dev/ttyS1 References: Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: > >What is connected to the serial port ? When I enable RTS/CTS on ttyS1 > >and there is my Epson 740 attached, the whole system freezed. > > Same thing attached. It could be a bug in the serial driver, but I don't think so. BeOS hangs same way (although it's likely Be people "ported" Linux code into BeOS...). I spent a couple of days around the serial driver and I didn't find any bug. BTW under MacOS it works fine :-/ so what ??? > >I don't > >know why this happen exactly. It seems that the printer changes continuosly > >with very high frequency the state of CTS, which cause the serial driver > >to loop indefinitely. > > Ouch! Broken hardware... how can I document this is happening, so that > I can demand an answer from Epson ? To print under Linux I wrote a small prg which sends data to the printer very slowly bacause I couldn't find a way to know when the printer buffer gets filled. Somewhere at Epson (about older printers) I read that it should use starndard rts/cts flow control. Ah, I send data at 230400bps 8N2 (*2* stop bits) because the printer don't seem to be able to receive data so quickly (again, no problems with 8N1 under MacOS). > Or maybe I should just hack the serial driver to ignore this. :-6 > And WTF > is the serial driver doing looking at CTS on a port with no data?! CTS changes cause and interrupt. Bye. ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/