S3 Graphics, a company HTC is in the process of buying has sued Apple (again), this time accusing the company of violating two different patents, reports “FOSS Patents” (http://macte.ch/QYw5u).

S3 has asked infringing products — the iPhone, iPod touch, iPad and Macs — be barred from sale. A complaint with the U.S. International Trade Commission was accompanied by a federal lawsuit filed in U.S. District Court in the district of Delaware.

The beef between Apple and HTC/S3 started in March 2010 with Apple’s first ITC complaint against HTC. In May 2010, HTC retaliated with an ITC complaint against Apple, and S3 Graphics filed its first ITC complaint against Apple.

In July 2011 the U.S. International Trade Commission ruled that Mac OS X violates patents held by S3 Graphics, while the platform for the iPhone, iPod touch and iPad tablet doesn’t. The operating system on the Mac infringes two S3 patents related to graphics chips, Judge James Gildea said.

S3 Graphics makes image compression technology. If Gildea’s decision is upheld in a review by the full six-member commission, the ITC can ban U.S. imports of some Macs.

Macs that have Nvidia graphics processing units have an implied license to the patents, the judge said. Gildea found that two other S3 patents were invalid, as were aspects of the two patents found to be infringed. The iPhone and iPad are no longer under threat of a ban from the S3 case.

— Dennis Sellers