Date: Mon, 13 Aug 2018 22:15:29 +0200 From: Alexander Lochmann <alexander.lochmann@tu-dortmund.de> To: Eugene Grosbein <eugen@grosbein.net>, freebsd-stable@freebsd.org Subject: Re: FreeBSD blocks on BOCHS serial port Message-ID: <661e5d36-6684-fae5-b325-f02ad570f2b4@tu-dortmund.de> In-Reply-To: <bc8f5df6-e338-a9fd-bdd7-e7e146cbcee7@grosbein.net> References: <e0c6883a-ed3c-c48e-6821-05d0aa3eb034@tu-dortmund.de> <bc8f5df6-e338-a9fd-bdd7-e7e146cbcee7@grosbein.net>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --f0thOhpCELH0FtOzDCrS8wBjUSfHCH7xL Content-Type: multipart/mixed; boundary="ZY8nTSAkxRjtHmIRZuAJc1WBjADAcnVLE"; protected-headers="v1" From: Alexander Lochmann <alexander.lochmann@tu-dortmund.de> To: Eugene Grosbein <eugen@grosbein.net>, freebsd-stable@freebsd.org Message-ID: <661e5d36-6684-fae5-b325-f02ad570f2b4@tu-dortmund.de> Subject: Re: FreeBSD blocks on BOCHS serial port References: <e0c6883a-ed3c-c48e-6821-05d0aa3eb034@tu-dortmund.de> <bc8f5df6-e338-a9fd-bdd7-e7e146cbcee7@grosbein.net> In-Reply-To: <bc8f5df6-e338-a9fd-bdd7-e7e146cbcee7@grosbein.net> --ZY8nTSAkxRjtHmIRZuAJc1WBjADAcnVLE Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 13.08.2018 21:36, Eugene Grosbein wrote: > 13.08.2018 20:52, Alexander Lochmann wrote: >=20 >> Hi folks! >> >> We are doing some automatic experiments using FreeBSD running in a >> virtual machine. >> To control the experiment from the outside, we use serial ports to >> communicate with an userspace program. >> The communication via serial does work with QEMU. However, it does not= >> work with BOCHS which is our desired emulator. >> Even simple operations like 'echo FOO | tee /dev/ttyu1' or 'cat >> /dev/ttyu1' do not work. Both commands block 'forever'. >> It does not matter whether we use ttyu0 (file backend) or ttyu1 (tcp >> socket). >> I put some debug output in sys/dev/uart/uart_dev_ns8250.c. The output >> suggests that the driver more or less reads and writes to the serial >> ports. At least it does something... >> >> Do you have any hints how we can further analyze this problem? >> Did anyone came across a similar problem? >=20 > This could be modem control line "Carrier Detection" (CD) or flow contr= ol problem: > emulators can have distinct default settings for serial ports. >=20 > You should not rely on defaults and make sure you disable modem control= /CD > either explicitly (using stty(1) etc.) or implicitly by switching to /d= ev/cuau0 > instead of /dev/ttyu0. Flow control settings should match too, for both= sides > of virtual port. Thx. I cannot even run 'stty < /dev/ttyu1' to see the current settings. It simply blocks... 'stty < /dev/ttyu0' works perfectly. ttyu0 uses a file-based backend. Whereas ttyu1 uses a tcp server-based backend with a connected netcat. >=20 >=20 --=20 Technische Universit=C3=A4t Dortmund Alexander Lochmann PGP key: 0xBC3EF6FD Otto-Hahn-Str. 16 phone: +49.231.7556141 D-44227 Dortmund fax: +49.231.7556116 http://ess.cs.tu-dortmund.de/Staff/al --ZY8nTSAkxRjtHmIRZuAJc1WBjADAcnVLE-- --f0thOhpCELH0FtOzDCrS8wBjUSfHCH7xL Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEElhZsUHzVP0dbkjCRWT7tBbw+9v0FAltx5uIACgkQWT7tBbw+ 9v1zng//Wxrt7QjZEqbyvyhiDjBCD2bSu9QZI/fuHzNC6ts/6foPiTsHg9DIORDF wQfbZlqKI14Mb50/qnie9p8SmB1bCs40eXE7vresM7awzzK9hf0CeRVO1JMSfnHL We8GC39cAnG2lpsLJqvL3V+hfMD7Ev2PJ4LavrAC7h1mdnBHrHr3ApwvxcqXtmtH wrI8XcYnbL0rdqoMRtgGOXvNDGxZUzrUQUFMR16Dyojsfx/VMJwXCnnW6R+E+8sG 0haLfLS4XtxFlPcNHlFOP9xY73bl6ThWLiN5AVL+ExeGyj8AZHYW/l+M21LvgOer xBRRIO/JAUaB6rSEQPUTKSAD0nBEy3H7Ib/XKdnx55HaGL4eCM+xy/HpxOI8LWgu HPouz0/goEpCcydI5mg3ucEkkmqFFje3vKShPMSlbad/zlgOyexRNgq376m4GmDV BUxJbXZe5ZJltSuKfsMPmMT9PBIfrXf7SRm2/WQLr13BwKRRTsdburxaIJm31fqf IsS2vlsh4JsVXhd5XP0QBXz3cHdrKdMmfJ5TozE4Lj7Phwxemdkh7yJeFB3VKeHS QjZwgxXL7uMfsyNal+LEQ4h2spaKwg7SSiuCl03MQ0MLETcKZqCvFRGzret5StAi 6GjVxj9VXHBUNsN+7skuw0ZFEYxZWghJ5GogRfaTVX94TDNBgxM= =uqRA -----END PGP SIGNATURE----- --f0thOhpCELH0FtOzDCrS8wBjUSfHCH7xL--
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