drm/i915: Only dump GPU state on set-wedged if interesting

As we may frequently mark the device as wedged to flush requests off it
during the normal course of events, quite often we have a large state
dump that is of no interest. Don't bother dumping it all if the engines
are all idle.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190115122057.1677-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -3178,7 +3178,7 @@ void i915_gem_set_wedged(struct drm_i915_private *i915)
 
 	GEM_TRACE("start\n");
 
-	if (GEM_SHOW_DEBUG()) {
+	if (GEM_SHOW_DEBUG() && !intel_engines_are_idle(i915)) {
 		struct drm_printer p = drm_debug_printer(__func__);
 
 		for_each_engine(engine, i915, id)