[Intel-gfx] [PATCH] drm/i915: Wedge the GPU if command parser setup fails

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Commit 311a50e76a33 ("drm/i915: Add support for mandatory cmdparsing")
introduced mandatory command parsing but setup failures were not
translated into wedging the GPU which was probably the intent.

Possible errors come in two categories. Either the sanity check on
internal tables has failed, which should be caught in CI unless an
affected platform would be missed in testing; or memory allocation failure
happened during driver load, which should be extremely unlikely but for
correctness should still be handled.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Fixes: 311a50e76a33 ("drm/i915: Add support for mandatory cmdparsing")
Cc: Jon Bloomfield <jon.bloomfield at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Chris Wilson <chris.p.wilson at intel.com>
---
To catchup with referenced patch we'd need to copy stable from v5.4+.
Failures are very unlikely but I think it would still be prudent to do so.
---
 drivers/gpu/drm/i915/gt/intel_engine_cs.c |  8 +++++++-
 drivers/gpu/drm/i915/i915_cmd_parser.c    | 19 +++++++++++++------
 drivers/gpu/drm/i915/i915_drv.h           |  2 +-
 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 577ebd4a324f..ac6478c4ede4 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -696,6 +696,11 @@ static int engine_setup_common(struct intel_engine_cs *engine)
 		goto err_status;
 	}
 
+	err = intel_engine_init_cmd_parser(engine);
+	if (err) {
+		goto err_cmd_parser;
+	}
+
 	i915_sched_init(&engine->sched,
 			engine->i915->drm.dev,
 			engine->name,
@@ -703,7 +708,6 @@ static int engine_setup_common(struct intel_engine_cs *engine)
 			ENGINE_PHYSICAL);
 
 	intel_engine_init_execlists(engine);
-	intel_engine_init_cmd_parser(engine);
 	intel_engine_init__pm(engine);
 	intel_engine_init_retire(engine);
 
@@ -720,6 +724,8 @@ static int engine_setup_common(struct intel_engine_cs *engine)
 
 	return 0;
 
+err_cmd_parser:
+	intel_breadcrumbs_free(engine->breadcrumbs);
 err_status:
 	cleanup_status_page(engine);
 	return err;
diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index ced9a96d7c34..13905891aff7 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -940,7 +940,7 @@ static void fini_hash_table(struct intel_engine_cs *engine)
  * struct intel_engine_cs based on whether the platform requires software
  * command parsing.
  */
-void intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
+int intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
 {
 	const struct drm_i915_cmd_table *cmd_tables;
 	int cmd_table_count;
@@ -948,7 +948,7 @@ void intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
 
 	if (!IS_GEN(engine->i915, 7) && !(IS_GEN(engine->i915, 9) &&
 					  engine->class == COPY_ENGINE_CLASS))
-		return;
+		return 0;
 
 	switch (engine->class) {
 	case RENDER_CLASS:
@@ -1013,19 +1013,19 @@ void intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
 		break;
 	default:
 		MISSING_CASE(engine->class);
-		return;
+		goto out;
 	}
 
 	if (!validate_cmds_sorted(engine, cmd_tables, cmd_table_count)) {
 		drm_err(&engine->i915->drm,
 			"%s: command descriptions are not sorted\n",
 			engine->name);
-		return;
+		goto out;
 	}
 	if (!validate_regs_sorted(engine)) {
 		drm_err(&engine->i915->drm,
 			"%s: registers are not sorted\n", engine->name);
-		return;
+		goto out;
 	}
 
 	ret = init_hash_table(engine, cmd_tables, cmd_table_count);
@@ -1033,10 +1033,17 @@ void intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
 		drm_err(&engine->i915->drm,
 			"%s: initialised failed!\n", engine->name);
 		fini_hash_table(engine);
-		return;
+		goto out;
 	}
 
 	engine->flags |= I915_ENGINE_USING_CMD_PARSER;
+
+out:
+	if (intel_engine_requires_cmd_parser(engine) &&
+	    !intel_engine_using_cmd_parser(engine))
+		return -EINVAL;
+	else
+		return 0;
 }
 
 /**
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f8413b3b9da8..c8b04b0ec919 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1946,7 +1946,7 @@ const char *i915_cache_level_str(struct drm_i915_private *i915, int type);
 
 /* i915_cmd_parser.c */
 int i915_cmd_parser_get_version(struct drm_i915_private *dev_priv);
-void intel_engine_init_cmd_parser(struct intel_engine_cs *engine);
+int intel_engine_init_cmd_parser(struct intel_engine_cs *engine);
 void intel_engine_cleanup_cmd_parser(struct intel_engine_cs *engine);
 int intel_engine_cmd_parser(struct intel_engine_cs *engine,
 			    struct i915_vma *batch,
-- 
2.27.0