Date: Thu, 06 Mar 1997 16:54:32 -0500 From: dennis <dennis@etinc.com> To: Terry Lambert <terry@lambert.org>, bmcgover@cisco.com (Brian McGovern) Cc: hackers@FreeBSD.ORG Subject: Re: Porting device drivers... Message-ID: <3.0.32.19970306165429.00afdcd0@etinc.com>
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At 01:12 PM 3/6/97 -0700, Terry Lambert wrote: >> I'm curious if anyone has any comments on the feasability of "porting" >> Linux device drivers to FreeBSD. I'm looking at doing a driver for the >> Cyclom Z card, and there is one that currently works for Linux. I'm >> wondering if its worth my time trying to recode it, or whether I should >> just start from scratch. > >Linus treats the kernel services exported to drivers as if the >kernel were a library distributed under the LGPL. This lets him >get away with a GPL'ed kernel that does not cause commercial >drivers to become GPL'ed. The Linux statement of license makes >this very clear. > >Because of this, I believe that any driver that can be loaded as >an LKM satisfies both the LPGL relink clause, and the GPL agregation >clause. Several lawyers have agreed with this intepretation at >various commercial companies (hence the availability of commercial >drivers for Linux). > >Conversely, then, any driver that can be LKM'ed will satisfy those >clauses in the BSD environment as well. > >The one problem you will have is with boot-critical devices: drivers >for them must be loaded as part of the kernel load. You should attempt >to convince the driver authors to reclassify their drivers under LGPL, >if you can, if they are boot-critical drivers (disk controllers, and >so on), or, ideally, release them under UCB license as well. > >This is actually one of the driving factors in my advocacy of VM86() >fallback drivers: boot critical devices can all have specific drivers >LKM'ed, as long as you can get to the point where you can load modules >at all before you need them, so the Linux drivers under GPL can still >be safely used by BSD via post-boot loading using the fallback drivers. > >Unless this card is used for a serial console (ie: it's boot-critical), >there's no reason you can't make it an LKM, and allow users to locally >create statically linked kernels, which would be non-redistributable >because of the conflict between the GPL "no additional restrictions" >and the UCB "claim credit" clauses. Why is this an issue, providing that the resulting BSD drivers include source code? The distinction is not "commercial", but that of source code. You certainly cannot take linux source and make an object distribution in 'BSD, but I dont believe that there is anything in the GPL license that makes code written for linux bound to linux only..... the only stipulation is that the modified source be made available. Another caveat is that the author of the code may be able to license it to you or simply give permission to do whatever you want with it..Under US law (at least) copyrights are always retained by the author, which would imply that even if a driver were released for Linux under GPL, the author would have the right to do whatever he wants with the code as it inherently belongs to him. Dennis
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