nVidia appears to be aiming very broadly with some of those claims; any validity will of course come down to the specifics of the implementations of each idea.
They'll need to be careful with some of their targets. Imagination has been at graphics as long as anyone (HTC's stab at Apple/ImgTec using S3's old patents didn't amount to much), and the Adreno architecture originated from work done by ATi and potentially some BitBoys involvement. On a relative scale, Mali, originating from the grad school work I think of the founders of the old Falanx is newish, but the details of some of these architectures/pipelines (especially PowerVR) makes them seem fairly unique.
In the case of qualcomm, one would have to dig up the exact details of the sale of the mobile biz to qualcomm. I cannot off the top of my head if the sale to qualcomm included actual patents or only licenses to patents. And even if the ATI/Nvidia patent cross license dated to that period, that doesn't mean that indemnity from that cross license actually transferred to any of the designs sold to qualcomm.
As far as being careful with their targets, Nvidia are being very careful. In the case of Samsung, it is highly unlikely that Samsung has any significant IP with which to attack Nvidia in the SoC market that isn't already covered by existing x-licensing agreements with other semiconductor fabricators. In the case of Qualcomm, most of Qualcomm's IP is actually tied to compulsory licensing infrastructure (AKA modem IP wrt 3G/4G, yes they do make a lot of money off if, but the licenses are generally compulsory due to their standard inclusion). As far as graphics, it is unlikely that Qualcomm has any significant/relevant IP due to how they entered the market, and the low likelyhood that ATI actually included actual patents vs perpetual rights to use.
It is also unlikely that either of Samsung's other potential suppliers of GPU IP want to voluntarily enter into the court case with Nvidia. It makes little sense for IMG to voluntarily indemnify Samsung in this case, esp, when IMG and Nvidia don't have an existing x-license and may or may not be negotiating one. We have no clue about the existing x-license relationships of other IMG licensees other than Intel with is fully indemnified by their existing x-license with Nvidia. It is unlikely that Apple is currently in any direct danger with of being sued by Nvidia (due to existing biz relationships) and may already have or be in the process of negotiating various license agreements with Nvidia. And Apple probably actually has some relevant IP making the fight more difficult.
Which leaves ARM. It is unknown what if any x-license agreements exist between ARM and Nvidia, but its unlikely based on reported information that any exist wrt graphics based on the suit and PR. However, it is highly likely that Nvidia already has a full license to particular core designs and a full architectural license which means that ARM has little leverage WRT to Nvidia, esp if Nvidia doesn't directly go after ARM per se wrt Mali. AKA, the ARM/Nvidia license agreement does probably have some legal impact if Nvidia was suing ARM directly, but likely has little relavence WRT to Nvidia suing a third party over the same IP (AKA the ARM lawyers probably didn't think of this scenario).
This suit certainly looks like Nvidia did their homework and decided to sue the two companies with both the largest liability and the weakest ability to defend themselves in a patent battle.
