From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <453FCA64.9090402@domain.hid> Date: Wed, 25 Oct 2006 22:34:44 +0200 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Xenomai-help] RTDM/ALSA hybrid driver ? References: <200610251610.36530.witzel.thomas@domain.hid> In-Reply-To: <200610251610.36530.witzel.thomas@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigCFDEB6918BEFFAA7E16281AF" Sender: jan.kiszka@domain.hid List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: witzel.thomas@domain.hid Cc: xenomai@xenomai.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigCFDEB6918BEFFAA7E16281AF Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Thomas Witzel wrote: > Hello, >=20 > I'm now trying to create a sound driver that will start and stop playba= ck in=20 > real time. Is it better to implement a driver for RTDM from scratch, or= is it=20 > reasonable to just add a RTDM interface for the required functionality = to an=20 > existing ALSA driver ? The advantage of the latter approach is of cours= e,=20 > that everything that doesn't need to be done in realtime already exists= =20 > through ALSA and I only would have to implement the pcm triggers throug= h=20 > RTDM. Is that reasonable at all ? Yes, this can be reasonable. You will fork the driver effectively, but you should be able to reuse init/cleanup parts for this. Basically, this is how most RTnet drivers were developed. But how hard and how tight are your RT requirements? I'm asking because I know that a lot of people are using unmodified ALSA drivers over the PREEMPT_RT kernel for real-time recording, processing, and playback. Maybe this can already provide you what you need. But I don't know the internal design of ALSA, if there are any pitfalls hidden like dynamic buffer management. Jan --------------enigCFDEB6918BEFFAA7E16281AF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFFP8pkniDOoMHTA+kRAlb9AJ4xpq8+Wuedqm/GTsQn2lhZLPvS8wCaAnEK WapXV6Po11AzczzCiFyD90A= =GAa0 -----END PGP SIGNATURE----- --------------enigCFDEB6918BEFFAA7E16281AF--