One thing you could try is to grab the latest verion of intel-gpu-tools from git and run the testsuite with make test. That should give you a nice set of failing tests with "tiled" in their names.
Then try to decrease the amount of memory linux uses with the mem=xxxm boot parameter, until all these tests with 'tiled' work reliably. The best result would be to figure out that things work for mem=xxxm, but not for mem=xxx+1m.
One thing you could try is to grab the latest verion of intel-gpu-tools from git and run the testsuite with make test. That should give you a nice set of failing tests with "tiled" in their names.
Then try to decrease the amount of memory linux uses with the mem=xxxm boot parameter, until all these tests with 'tiled' work reliably. The best result would be to figure out that things work for mem=xxxm, but not for mem=xxx+1m.