Garmin believes that its semiconductor chip suppliers have indemnification obligations to defend Garmin in this matter

Well Garmin if you purchased your chips from Infineon I think you're screwed. This is from one of Infineons contracts. Yes they do indemnify but as you can see in 8.2( iv) the MMP is your problem. I don't know who Garmin buys chips from but I do know I would immediately head down stream from Infineon and cast a line. Maybe a net would be better.

8.2. Notwithstanding the foregoing, any liability of Seller shall be excluded:
(i) if the infringement of IP Rights is not caused by the product itself, for example if such infringement results from the application of the product (including any application-specific circuitry implemented in the products), regardless of whether Seller was aware of or had been notified of such use; or
(ii) if the infringement of IP Rights results from specifications or instructions given by Buyer or the fact that the products have been changed by Buyer or are being used in conjunction with products not delivered by Seller, which convert otherwise non-infringing products to infringing products; or
(iii) if the IP Rights are essential for the compliance with industry standards. For the purposes of this Order, essential as applied to IP Rights shall mean that it is not possible on technical grounds (where no commercially reasonable alternative exists), taking into account normal technical practice and the state of the art generally available at the time of standardization, that the products and the technology incorporated therein comply with the relevant industry standards without infringing such IP Right; or
(iii) if infringement of IP Rights claim is made after 24 months starting on the date the risk of loss or damage has passed to Buyer according to Section 6; or
(iv) if infringement pertains to or based on the Moore Microprocessor Patent Portfolio (including without limitation the US Patent US 5,440,749 or European Patent EP 0 870 226 or any patents claiming priority of one of these patents).