Date: Fri, 31 Aug 2007 14:01:00 +0200 From: Alexander Leidinger <Alexander@Leidinger.net> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: arch@freebsd.org Subject: Re: Proof of concept: soundcard as console device Message-ID: <20070831140100.zphn2zsxzb408okc@webmail.leidinger.net> In-Reply-To: <8412.1188553371@critter.freebsd.dk> References: <8412.1188553371@critter.freebsd.dk>
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Quoting Poul-Henning Kamp <phk@phk.freebsd.dk> (from Fri, 31 Aug 2007 =20 09:42:51 +0000): > > Yesterday while I was futzing with my new laptop and ACPI suspend/resume, > I once again found myself cursing the nutjob who took away our serial > ports. Lucky those people with a firewire interface... > Then my mind wandered around a bit and suddenly it struck me: all > modern hardware have built in AC97 sound hardware, and it offers a > channel with a pretty decent bandwidth. You are too late, Intel is moving to HDA and away of AC97. And it =20 seems everyone except Creative is following (there are companies with =20 their own interfaces (VIA envy24), but often they provide a HDA =20 chipset too). Creative doesn't really matter, as they don't provide =20 docs and everyone tries to avoid it. > This morning I ran a simple experiment, from userland, but the > result show clearly that the idea is workable. > > The transmission format I used: send a negative transient to start > a character and after N samples, send a positive transient, where > N is the ASCII value of the character + a small constant. Some cards have digital-out/in (SPDIF), maybe it's an option for you. Bye, Alexander. --=20 Never give an inch! http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID =3D B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID =3D 72077137
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