Re: [comedi] Fail to use out-of-tree comedi on debian
Cédric Boudinet <[email protected]> Tue, 30 Sep 2025 12:58:06 -0700 (PDT)
| Newsgroups | gmane.linux.comedi |
|---|---|
| Message-ID | <[email protected]> |
------=_Part_121882_749835560.1759262286141 Content-Type: multipart/alternative; boundary="----=_Part_121883_1816700165.1759262286141" ------=_Part_121883_1816700165.1759262286141 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Dear Ian I managed to built both in-tree and out-of-tree dt9812 modules and the=20 iocard works as expected. I can now work on the driver. Thanks a lot. Cedric On Tuesday, 30 September 2025 at 15:25:42 UTC+2 Ian Abbott wrote: > On 30/09/2025 13:36, Ian Abbott wrote: > > On 30/09/2025 09:02, C=C3=A9dric Boudinet wrote: > >> Hello > >> > >> I would like to improve the comedi driver for the dt9812 card. > >> I a working on debian Trixie. I tried to rebuild and install using=20 > >> dkms with the master version from git (https://github.com/Linux-=20 > >> Comedi/ comedi/blob/master/INSTALL.md#running-comedi). > >> The build process and install works fine (modinfo loads comedi.ko.xz= =20 > >> and dt9812.ko.xz from /lib/modules/6.12.48+deb13-amd64/updates/dkms/). > >> > >> However when I plug the iocard, dmesg shows the following errors: > [snip] > >> And no /dev/comedi0 is created. Do you know where the problem is=20 > >> coming from? Should I rebuild comedilib as well? Or maybe should I=20 > >> rebuilt from the debian kernel source? > >> > >> Bests > >> Cedric > >=20 > > I guess the cause is indicated by this message: > >=20 > > [ 1108.696688] transfer buffer is on stack > >=20 > > The Linux kernel in-tree Comedi USB drivers allocate USB command buffer= s=20 > > from kmalloc memory, due to stack memory not being supported on some=20 > > architectures for DMA. I guess "some architectures" now includes=20 > > x86-64, which it never used to. > > I've pushed a commit to the Comedi GitHub repo to hopefully correct this= =20 > problem, based on code in the Linux kernel in-tree version of the driver= =20 > to replace the on-stack buffers with temporary kmalloc'ed buffers=20 > (actually kzalloc to zero-fill the allocated buffers). > > Please let me know if it works if you get the chance to test it. > > There may be similar problems in the other out-of-tree USB Comedi=20 > drivers, but I'm looking into that now. > > --=20 > -=3D( Ian Abbott <[email protected]> || MEV Ltd. is a company )=3D- > -=3D( registered in England & Wales. Regd. number: 02862268. )=3D- > -=3D( Regd. addr.: S11 & 12 Building 67, Europa Business Park, )=3D- > -=3D( Bird Hall Lane, STOCKPORT, SK3 0XA, UK. || www.mev.co.uk )=3D- > --=20 You received this message because you are subscribed to the Google Groups "= Comedi: Linux Control and Measurement Device Interface" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/comedi_list= /781f991a-51ad-46d8-b924-2a000b7cfef2n%40googlegroups.com. ------=_Part_121883_1816700165.1759262286141 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div>Dear Ian</div><div>I managed to built both in-tree and out-of-tree dt9= 812 modules and the iocard works as expected.</div><div>I can now work on t= he driver.</div><div>Thanks a lot.</div><div>Cedric</div><br /><div class= =3D"gmail_quote"><div dir=3D"auto" class=3D"gmail_attr">On Tuesday, 30 Sept= ember 2025 at 15:25:42 UTC+2 Ian Abbott wrote:<br/></div><blockquote class= =3D"gmail_quote" style=3D"margin: 0 0 0 0.8ex; border-left: 1px solid rgb(2= 04, 204, 204); padding-left: 1ex;">On 30/09/2025 13:36, Ian Abbott wrote: <br>> On 30/09/2025 09:02, C=C3=A9dric Boudinet wrote: <br>>> Hello <br>>> <br>>> I would like to improve the comedi driver for the dt9812 card. <br>>> I a working on debian Trixie. I tried to rebuild and install u= sing=20 <br>>> dkms with the master version from git (<a href=3D"https://gith= ub.com/Linux-" target=3D"_blank" rel=3D"nofollow" data-saferedirecturl=3D"h= ttps://www.google.com/url?hl=3Den-GB&q=3Dhttps://github.com/Linux-&= source=3Dgmail&ust=3D1759348570029000&usg=3DAOvVaw3LrjvZ-GlTrFwifQa= oz9Gd">https://github.com/Linux-</a>=20 <br>>> Comedi/ comedi/blob/master/INSTALL.md#running-comedi). <br>>> The build process and install works fine (modinfo loads comedi= .ko.xz=20 <br>>> and dt9812.ko.xz from /lib/modules/6.12.48+deb13-amd64/updates= /dkms/). <br>>> <br>>> However when I plug the iocard, dmesg shows the following erro= rs: <br>[snip] <br>>> And no /dev/comedi0 is created. Do you know where the problem = is=20 <br>>> coming from? Should I rebuild comedilib as well? Or maybe shou= ld I=20 <br>>> rebuilt from the debian kernel source? <br>>> <br>>> Bests <br>>> Cedric <br>>=20 <br>> I guess the cause is indicated by this message: <br>>=20 <br>> [ 1108.696688] transfer buffer is on stack <br>>=20 <br>> The Linux kernel in-tree Comedi USB drivers allocate USB command b= uffers=20 <br>> from kmalloc memory, due to stack memory not being supported on so= me=20 <br>> architectures for DMA.=C2=A0 I guess "some architectures"= ; now includes=20 <br>> x86-64, which it never used to. <br> <br>I've pushed a commit to the Comedi GitHub repo to hopefully correct= this=20 <br>problem, based on code in the Linux kernel in-tree version of the drive= r=20 <br>to replace the on-stack buffers with temporary kmalloc'ed buffers= =20 <br>(actually kzalloc to zero-fill the allocated buffers). <br> <br>Please let me know if it works if you get the chance to test it. <br> <br>There may be similar problems in the other out-of-tree USB Comedi=20 <br>drivers, but I'm looking into that now. <br> <br>--=20 <br>-=3D( Ian Abbott <<a href data-email-masked rel=3D"nofollow">abb...@= mev.co.uk</a>> || MEV Ltd. is a company )=3D- <br>-=3D( registered in England & Wales. Regd. number: 02862268. )=3D= - <br>-=3D( Regd. addr.: S11 & 12 Building 67, Europa Business Park, )=3D= - <br>-=3D( Bird Hall Lane, STOCKPORT, SK3 0XA, UK. || <a href=3D"http://www.= mev.co.uk" target=3D"_blank" rel=3D"nofollow" data-saferedirecturl=3D"https= ://www.google.com/url?hl=3Den-GB&q=3Dhttp://www.mev.co.uk&source=3D= gmail&ust=3D1759348570030000&usg=3DAOvVaw1CLlQrIV1EWgpXXCsXr0nl">ww= w.mev.co.uk</a> )=3D- <br></blockquote></div> <p></p> -- <br /> You received this message because you are subscribed to the Google Groups &= quot;Comedi: Linux Control and Measurement Device Interface" group.<br= /> To unsubscribe from this group and stop receiving emails from it, send an e= mail to <a href=3D"mailto:[email protected]">comedi_= [email protected]</a>.<br /> To view this discussion visit <a href=3D"https://groups.google.com/d/msgid/= comedi_list/781f991a-51ad-46d8-b924-2a000b7cfef2n%40googlegroups.com?utm_me= dium=3Demail&utm_source=3Dfooter">https://groups.google.com/d/msgid/comedi_= list/781f991a-51ad-46d8-b924-2a000b7cfef2n%40googlegroups.com</a>.<br /> ------=_Part_121883_1816700165.1759262286141-- ------=_Part_121882_749835560.1759262286141--