From owner-freebsd-hardware Sat Feb 12 15:14:35 2000 Delivered-To: freebsd-hardware@freebsd.org Received: from polaris.we.lc.ehu.es (polaris.we.lc.ehu.es [158.227.6.43]) by builder.freebsd.org (Postfix) with ESMTP id 8CD494019 for ; Sat, 12 Feb 2000 15:14:31 -0800 (PST) Received: from we.lc.ehu.es (lxpxfs.lx.ehu.es [158.227.99.248]) by polaris.we.lc.ehu.es (8.9.1/8.9.1) with ESMTP id AAA07240; Sun, 13 Feb 2000 00:14:20 +0100 (MET) Message-ID: <38A5E94B.397E77BC@we.lc.ehu.es> Date: Sun, 13 Feb 2000 00:14:19 +0100 From: "Jose M. Alcaide" Organization: Universidad del =?iso-8859-1?Q?Pa=EDs?= Vasco - Dpto. de Electricidad y =?iso-8859-1?Q?Electr=F3nica?= X-Mailer: Mozilla 4.7 [en] (X11; U; FreeBSD 3.4-RELEASE i386) X-Accept-Language: es-ES, es, en-US, en MIME-Version: 1.0 To: Bruce Evans Cc: freebsd-hardware@FreeBSD.ORG Subject: Re: [fix and RFC] interrupt-level buffer overflows with Xircom PCMCIAmodem References: Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Bruce Evans wrote: > > On Sat, 12 Feb 2000, Jose M. Alcaide wrote: > > > Now, the conclusions: perhaps RS_IBUFSIZE=256 is too low for some devices > > (notably internal modems); it's only a theory. Or perhaps some devices > > Too large for devices with broken 16550 emulation. Uh? Are you saying that I should decrement RS_IBUFSIZE instead of incrementing it? I could test this, but I don't see how a shorter buffer could help to avoid buffer overruns... > RTS emulation is probably also broken for there to be a problem. Ideally, > the sender should check its version of RTS (i.e., CTS) before sending > each character. For bug for bug compatibility with 16550 senders, the > sender only needs to check it every 16th character. I could insert some "probes" in sio.c to see what happens with RTS/CTS, but I am not a 16550 expert, so I need some advice :-) > RS_IBUFSIZE doesn't exist in -current. Instead, the buffer is sized to > hold 4 ticks (4.0 / hz seconds) worth of input at the current input speed > (or 128 bytes if that is larger). Ah! Unfortunately I am not running -CURRENT on my laptop. I should have checked -CURRENT's sio.c before suggesting that kernel config option. Sorry. Thanks very much, -- JMA ----------------------------------------------------------------------- José Mª Alcaide | mailto:jose@we.lc.ehu.es Universidad del País Vasco | mailto:jmas@FreeBSD.org Dpto. de Electricidad y Electrónica | http://www.we.lc.ehu.es/~jose Facultad de Ciencias - Campus de Lejona | Tel.: +34-946012479 48940 Lejona (Vizcaya) - SPAIN | Fax: +34-946013071 ----------------------------------------------------------------------- "Beware of Programmers who carry screwdrivers" -- Leonard Brandwein To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message