drm/i915/selftests: Improve switch-to-kernel-context checking

We can reduce the switch-to-kernel-context selftest to operate as a loop
and so trivially test another state transition (that of idle->busy).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190307211947.6954-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index 0346ff224d5d29e206c431514ce1575a3cabf53d..755c4a7304b2a565688e358be81d14951fbc0192 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -1493,63 +1493,55 @@ static int __igt_switch_to_kernel_context(struct drm_i915_private *i915,
 {
        struct intel_engine_cs *engine;
        unsigned int tmp;
-       int err;
+       int pass;
 
        GEM_TRACE("Testing %s\n", __engine_name(i915, engines));
-       for_each_engine_masked(engine, i915, engines, tmp) {
-               struct i915_request *rq;
+       for (pass = 0; pass < 4; pass++) { /* Once busy; once idle; repeat */
+               bool from_idle = pass & 1;
+               int err;
 
-               rq = i915_request_alloc(engine, ctx);
-               if (IS_ERR(rq))
-                       return PTR_ERR(rq);
+               if (!from_idle) {
+                       for_each_engine_masked(engine, i915, engines, tmp) {
+                               struct i915_request *rq;
 
-               i915_request_add(rq);
-       }
+                               rq = i915_request_alloc(engine, ctx);
+                               if (IS_ERR(rq))
+                                       return PTR_ERR(rq);
 
-       err = i915_gem_switch_to_kernel_context(i915);
-       if (err)
-               return err;
-
-       for_each_engine_masked(engine, i915, engines, tmp) {
-               if (!engine_has_kernel_context_barrier(engine)) {
-                       pr_err("kernel context not last on engine %s!\n",
-                              engine->name);
-                       return -EINVAL;
+                               i915_request_add(rq);
+                       }
                }
-       }
 
-       err = i915_gem_wait_for_idle(i915,
-                                    I915_WAIT_LOCKED,
-                                    MAX_SCHEDULE_TIMEOUT);
-       if (err)
-               return err;
+               err = i915_gem_switch_to_kernel_context(i915);
+               if (err)
+                       return err;
 
-       GEM_BUG_ON(i915->gt.active_requests);
-       for_each_engine_masked(engine, i915, engines, tmp) {
-               if (engine->last_retired_context->gem_context != i915->kernel_context) {
-                       pr_err("engine %s not idling in kernel context!\n",
-                              engine->name);
+               if (!from_idle) {
+                       err = i915_gem_wait_for_idle(i915,
+                                                    I915_WAIT_LOCKED,
+                                                    MAX_SCHEDULE_TIMEOUT);
+                       if (err)
+                               return err;
+               }
+
+               if (i915->gt.active_requests) {
+                       pr_err("%d active requests remain after switching to kernel context, pass %d (%s) on %s engine%s\n",
+                              i915->gt.active_requests,
+                              pass, from_idle ? "idle" : "busy",
+                              __engine_name(i915, engines),
+                              is_power_of_2(engines) ? "" : "s");
                        return -EINVAL;
                }
-       }
 
-       err = i915_gem_switch_to_kernel_context(i915);
-       if (err)
-               return err;
+               /* XXX Bonus points for proving we are the kernel context! */
 
-       if (i915->gt.active_requests) {
-               pr_err("switch-to-kernel-context emitted %d requests even though it should already be idling in the kernel context\n",
-                      i915->gt.active_requests);
-               return -EINVAL;
+               mutex_unlock(&i915->drm.struct_mutex);
+               drain_delayed_work(&i915->gt.idle_work);
+               mutex_lock(&i915->drm.struct_mutex);
        }
 
-       for_each_engine_masked(engine, i915, engines, tmp) {
-               if (!intel_engine_has_kernel_context(engine)) {
-                       pr_err("kernel context not last on engine %s!\n",
-                              engine->name);
-                       return -EINVAL;
-               }
-       }
+       if (igt_flush_test(i915, I915_WAIT_LOCKED))
+               return -EIO;
 
        return 0;
 }
@@ -1593,8 +1585,6 @@ static int igt_switch_to_kernel_context(void *arg)
 
 out_unlock:
        GEM_TRACE_DUMP_ON(err);
-       if (igt_flush_test(i915, I915_WAIT_LOCKED))
-               err = -EIO;
 
        intel_runtime_pm_put(i915, wakeref);
        mutex_unlock(&i915->drm.struct_mutex);