From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43E9EEBA.1050405@domain.hid> Date: Wed, 08 Feb 2006 14:14:34 +0100 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Xenomai-help] RTDM mmap alternative References: <20060203192739.87567.qmail@domain.hid> <200602061900.35411.lbocseg@domain.hid> <43E8DB10.5000901@domain.hid> <200602081043.47859.lbocseg@domain.hid> In-Reply-To: <200602081043.47859.lbocseg@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig5B9621BC666523A80984E92A" 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: Rodrigo Rosenfeld Rosas Cc: xenomai-help This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig5B9621BC666523A80984E92A Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Rodrigo Rosenfeld Rosas wrote: >> ... >> I tested it (after figuring out what to do at all, and how to get it >> working then...) with a simple demo that returns a shared kernel memor= y >> block, mapped into user-space via an RTDM-IOCTL. I think you should >> easily (now really!) adapt it to your needs. Please check if this >> functions meets your requirements and works for more than one scenario= =2E >> If so, I will add it to official RTDM. >> >> >> @all: I would be curious to hear any comment on my /dev/zero-trick to >> invoke mmap in kernel-space. Is this an ugly hack or may it be worth >> considering to apply on /dev/rtheap as well - to overcome the need for= >> this device (and related user errors...)? >=20 > Jan, actually I didn't like the /dev/zero hack. If someone else is=20 > using /dev/zero it will result in a problem... I think it would be bett= er to=20 Why? It isn't an exclusive device. And I'm only invoking open/close on the original instance (which even have no handlers associated, see drivers/char/mem.c), mmap gets overloaded. > reserve a separate file descriptor for mmaping. Maybe in a separate mod= ule=20 > like xeno_mmap that only register a, say, /dev/xenommap or /dev/xenomai= /mmap.=20 > I think it would be a better approach. Or maybe something like=20 >=20 > void *rtdm_mmap_to_user(void *buffer, size_t length, char *dev_to_use) >=20 > Just some ideas... Maybe I'm overseeing something: Did you face real problems with my approa= ch? Jan --------------enig5B9621BC666523A80984E92A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFD6e66niDOoMHTA+kRAt2wAJ4o9ilLYweH5stCELhc+ntlliDCDgCeKvum MQSyBDR6xN56m3ME3zDghfE= =3yRi -----END PGP SIGNATURE----- --------------enig5B9621BC666523A80984E92A--