I thought those were just the closed source drivers from Nvidia, Intel, and so on. But those vendors might have licenses for this kind of patent, especially Nvidia?
Right, but I thought it matters only if you sell something globally. Linux is distributed for free, so the burden of patent compliance is on the user, isn't it?
Not a lawyer, but patent law refers to distribution too. It shouldn't matter if it's free or has a price if they can say you're distributing it to Brazilian users.
Distributing something for free doesn't mean you don't have patent obligations if you do it in the country that patent is valid in. On top of that, many corporations do sell their distribution of Linux.