https://01.org/linuxgraphics/gfx-docs/drm/admin-guide/tainte...
Edit:
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Good point about the distinction between adding modules modifying existing source. It is an interesting question, actually and I haven't been able to find an authoritative answer on the subject.
A patch is a description of changes that would be made to a work, if they were made. Does it trigger the licence before it is applied to the source tree? On the other hand to generate a patch you would require the original source (even if you write it by hand you would still have to look at the source to determine line numbers). An you will probably have some bits of the source in your diff, but they are not being used for anything other than position information.