Messages in this thread | | | From | Yann Droneaud <> | Date | Fri, 22 May 2015 12:05:48 +0200 | Subject | Re: Device Tree Blob (DTB) licence |
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Hi,
Le mardi 05 mai 2015 à 11:41 -0500, Rob Herring a écrit : > On Tue, May 5, 2015 at 5:05 AM, Yann Droneaud <ydroneaud@opteya.com> > wrote: > > > > I believe Device Tree Blob (.dtb file) built from kernel's Device > > Tree > > Sources (.dts, which #include .dtsi, which #include .h) using > > Device > > Tree Compiler (dtc) are covered by GNU General Public Licence v2 > > (GPLv2), but cannot find any reference. > > By default yes, but we've been steering people to dual license them > GPL/BSD. >
Can you give me the rationale behind such dual licenses requirement ?
If a BSD .dts includes GPLv2 .h, the whole is covered by GPLv2, so I cannot find a case where a BSD covered .dts file could be used alone within BSD license rights.
> > As most .dtsi in arch/arm/boot/dts/ are covered by GPLv2, and, > > as most .h in include/dt-bindings/ are also covered by GPLv2, > > the source code is likely covered by GPLv2. > > > > Then this source code is translated in a different language > > (flattened > > device tree), so the resulting translation is also likely covered > > by > > GPLv2. > > > > So, when I'm proposed to download a .dtb file from a random vendor, > > can I require to get the associated source code ? > > I believe so yes. However, you already have the "source" for the most > part. Just run "dtc -I dtb -O dts <dtb file>". You loose the > preprocessing and include structure though (not necessarily a bad > thing IMO). > > Then the question is what is the license on that generated dts! >
That's also a good question.
Is this a form a "reverse engineering" with all the legalese burden ?
Anyway without a clear information attached to the DTB, it's difficult to tell which licence cover the "decompiled" version.
> > Anyway, for a .dtb file generated from kernel sources, it's rather > > painful to look after all .dts, .dtsi, .h, to find what kind of > > licences are applicables, as some are covered by BSD, dual licensed > > (any combination of X11, MIT, BSD, GPLv2). > > I imagine the includes cause some licensing discrepancies if you dug > into it. >
It's a pity, and it's probably something to sort out.
DTB files produced as part of kernel compilation should have a well known license attached by default.
Regards.
-- Yann Droneaud OPTEYA
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