There are many very active threads concerning GPL and LGPL licenses in hardware. After reading most of them I fell like knowing even less than before. I tried to compress all the knowledge into just few sentences. Please correct me if I still misunderstand anything again.

1. I can use GPL IP core in the commercial design, but the source code of a design as a whole should be published also under GPL license. In other word, the design can not use any proprietary IP.

2. I can use LGPL IP core in the commercial design and I am forced to publish any changes to that particular IP. The design can contain proprietary IP and I am not forced to publish it.

Please correct me if I still misunderstand anything again.

Have you looked at the articles/presentations on GPL that have been given at the OpenRISC conferences? I found two references from the 2014 conference: Here and here.

My conclusion from these articles is that your conclusions above, while well reasoned, are not nearly so clear cut. Indeed, the meanings may be so ambiguous as to leave the ultimate interpretation up to the jury. That, I think, is why you feel so confused after reading so many articles. For example, does the source of the synthesis tool need to be included in order to use an open source design--in addition to whatever vendor supplied libraries? This isn't well documented or described.

Dan