message: Document skipping condition on i915-perf timelines
diff: @@ -75,6 +75,7 @@ int read_i915_perf_file( const char *file, StrPool &strpool, trace_info_t &trace
  for (uint32_t i = 0; i < reader->n_timelines; i++)
  {
  + // Skip the idle time
  if ( reader->timelines[i].hw_id == 0xffffffff )
  continue;
  