If you are setting up SharePoint 2013 and SQL 2012 with SharePoint Integration Mode please read on. You might be under impression you did everything properly but you get the following error when trying to deploy a report using BIDS or trying to edit a data source:
"The permissions granted to user ‘domain\username’ are insufficient for performing this operation. —> Microsoft.ReportingServices.Diagnostics.Utilities.AccessDeniedException: The permissions granted to user ‘domain\username’ are insufficient for performing this operation."
To solve this problem you have to grant your SQL Reporting Service Application Pool Account (whatever is running your SQL Service Application, see Central Admin -> Manage Service Application -> SQL Server Reporting Services) Full Control to the web application that report is being deployed to in your particular case.
Or you could just use the powershell command below:
$webApp = Get-SPWebApplication –Identity http://yoursharepointapp
$webApp.GrantAccessToProcessIdentity(“domain\SSRSAccount”)
Source: http://paulliebrand.com/
