From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43E4A102.4070207@domain.hid> Date: Sat, 04 Feb 2006 13:41:38 +0100 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Xenomai-help] RTDM mmap alternative References: <20060203192739.87567.qmail@domain.hid> <43E46EDA.7060304@domain.hid> <43E4A197.6030801@domain.hid> In-Reply-To: <43E4A197.6030801@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig8B1E131FEACE17530C7685A8" 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@xenomai.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig8B1E131FEACE17530C7685A8 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Rodrigo Rosenfeld Rosas wrote: > Hi, Jan. I think I wasn't very clear on my post. I'll try to clarify > what I meaned... >=20 > Jan Kiszka escreveu: >> Rodrigo Rosenfeld Rosas wrote: >> =20 >>> Hi Jan, I'm back on this discussion. >>> >>> At the time I asked you, you told me to do the mmap on driver >>> initialization. >>> >>> But now, I realized that, since I'll be using RTDM, how could I use >>> mmap from RTDM, even if in a non RT-context? >>> =20 >> >> Which mapping step are you now referring to, the one to get the large >> physical DMA area inside the kernel address space or the one to map >> kernel addresses to user space? > I'm refering to the second case. I want to map the kernel addresses to > user space but I'm not very sure if I can do the same thing I did in my= > previous mmap call on an ioctl. I mean, I don't know if the kernel does= > something else in a mmap call... And since I don't have a mmap handler > I'm a bit confusing... >=20 >> Already checked the related LDD3 chapter for this? >> =20 > Yes, but it didn't answered to my doubts... What precisely? I suggested to look at remap_pfn_range() or io_remap_page_range(). Do you see problems when using one of them? >>> I'm a bit confusing... >>> >>> What would be others alternatives for avoid copying the video frames >>> in a RTDM driver? >>> =20 >> >> Either map or copy, there is no third way. The point is just which >> mapping functions to use and when. >> =20 > That is what I would like to know... Which mapping functions are > available? Actually, if I can use the same I used on my previous mmap > handler that is good. I'm just unsure if something will be missing or > not... As I haven't written such a driver as well yet, I cannot say which one will fit. You will have to go though the LDD explanations and play with it (which means e.g. finding out where to obtain all required arguments - should be feasible). >=20 > I have also noted that there is no poll or select handler on RTDM. Are > there some plans to include them? >=20 Only rough plans. This requires a lot of work and restructuring, I'm afraid. And I doubt that it's worth it. Do you see an urgent use-case for poll/select under RT? The only real-life use-case that we came across was ACE/TAO. Jan --------------enig8B1E131FEACE17530C7685A8 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 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFD5KECniDOoMHTA+kRAmcRAJ9cEoi5oT7qK1Z5zmEWqkU/nW4X2ACZASQq 987TefUold2x5AdCG12Itms= =wPAc -----END PGP SIGNATURE----- --------------enig8B1E131FEACE17530C7685A8--