drm/i915/execlists: Leave tell-tales as to why pending[] is bad

Before we BUG out with bad pending state, leave a telltale as to which
test failed.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191010071434.31195-2-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index bd8ba98..fd609ce 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1089,25 +1089,45 @@ assert_pending_valid(const struct intel_engine_execlists *execlists,
 
        trace_ports(execlists, msg, execlists->pending);
 
-       if (!execlists->pending[0])
+       if (!execlists->pending[0]) {
+               GEM_TRACE_ERR("Nothing pending for promotion!\n");
                return false;
+       }
 
-       if (execlists->pending[execlists_num_ports(execlists)])
+       if (execlists->pending[execlists_num_ports(execlists)]) {
+               GEM_TRACE_ERR("Excess pending[%d] for promotion!\n",
+                             execlists_num_ports(execlists));
                return false;
+       }
 
        for (port = execlists->pending; (rq = *port); port++) {
-               if (ce == rq->hw_context)
+               if (ce == rq->hw_context) {
+                       GEM_TRACE_ERR("Duplicate context in pending[%zd]\n",
+                                     port - execlists->pending);
                        return false;
+               }
 
                ce = rq->hw_context;
                if (i915_request_completed(rq))
                        continue;
 
-               if (i915_active_is_idle(&ce->active))
+               if (i915_active_is_idle(&ce->active)) {
+                       GEM_TRACE_ERR("Inactive context in pending[%zd]\n",
+                                     port - execlists->pending);
+                       return false;
+               }
+
+               if (!i915_vma_is_pinned(ce->state)) {
+                       GEM_TRACE_ERR("Unpinned context in pending[%zd]\n",
+                                     port - execlists->pending);
                        return false;
+               }
 
-               if (!i915_vma_is_pinned(ce->state))
+               if (!i915_vma_is_pinned(ce->ring->vma)) {
+                       GEM_TRACE_ERR("Unpinned ringbuffer in pending[%zd]\n",
+                                     port - execlists->pending);
                        return false;
+               }
        }
 
        return ce;

diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 6795f1d..db20d2b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -37,10 +37,8 @@ struct drm_i915_private;
 #define GEM_SHOW_DEBUG() (drm_debug & DRM_UT_DRIVER)
 
 #define GEM_BUG_ON(condition) do { if (unlikely((condition))) {        \
-               pr_err("%s:%d GEM_BUG_ON(%s)\n", \
-                      __func__, __LINE__, __stringify(condition)); \
-               GEM_TRACE("%s:%d GEM_BUG_ON(%s)\n", \
-                         __func__, __LINE__, __stringify(condition)); \
+               GEM_TRACE_ERR("%s:%d GEM_BUG_ON(%s)\n", \
+                             __func__, __LINE__, __stringify(condition)); \
                BUG(); \
                } \
        } while(0)
@@ -66,11 +64,16 @@ struct drm_i915_private;
 
 #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
 #define GEM_TRACE(...) trace_printk(__VA_ARGS__)
+#define GEM_TRACE_ERR(...) do {                                                \
+       pr_err(__VA_ARGS__);                                            \
+       trace_printk(__VA_ARGS__);                                      \
+} while (0)
 #define GEM_TRACE_DUMP() ftrace_dump(DUMP_ALL)
 #define GEM_TRACE_DUMP_ON(expr) \
        do { if (expr) ftrace_dump(DUMP_ALL); } while (0)
 #else
 #define GEM_TRACE(...) do { } while (0)
+#define GEM_TRACE_ERR(...) do { } while (0)
 #define GEM_TRACE_DUMP() do { } while (0)
 #define GEM_TRACE_DUMP_ON(expr) BUILD_BUG_ON_INVALID(expr)
 #endif