jQuery Grid Plugin - jqGrid

I want to know what the pattern/strategy is for validation for handling server-side errors during cell-editing as well as inline-editing?

1. What callback function can I use for inline editing when the server throws and error, seems cell-editing has some callback I can plug into that inline does not have?The issue I ran into is as follows to help explai the reason for my question, and let me know what is the recommended approach for solving it: Add a new address, requires street address 1, city, state, country and zip, but only requires state if country = USA or Canada and will not save the record to the database unless the entire record is correct, with inline editing there is no callback function I can plug into to handle this error and I wanted to use inline since the user needs to specify ALL required field before ajax call to save. However inline seems to not expose any call backs. So with cell-editing, each cell is saved individually, handels errors from server, but cannot save an address without a State unless the user marks the country as non USA or Canada, and the server also does not allow to change the country to non USA or Canada while a State is specified, catch 22, how should this situation be approached using jqGrid?

2. Also, what is the approach when using cell or inline editing when you want to add a new row?