Date: Sun, 13 Feb 2000 00:14:19 +0100 From: "Jose M. Alcaide" <jose@we.lc.ehu.es> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-hardware@FreeBSD.ORG Subject: Re: [fix and RFC] interrupt-level buffer overflows with Xircom PCMCIAmodem Message-ID: <38A5E94B.397E77BC@we.lc.ehu.es> References: <Pine.BSF.4.21.0002130354510.3031-100000@alphplex.bde.org>
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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
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