How to pass a multi valued parameter from master report to sub report

Hi 

I am trying pass a parameter from the main report to sub report but the thing is the parameters are getting passed but the values not getting fetched. based on the parameter.

my parameter name in both the reports are same and I am using the following query

Split(Join(Parameters!paramname.value,","), ",")

please suggest me what to do.

SQL Server Reporting Srevice 2012

Thanks

Subrat Kumar