drm/i915/guc: Add work queue to trigger a GT reset

The G2H handler needs to be flushed during a GT reset but a G2H
indicating engine reset failure can trigger a GT reset. Add a worker to
trigger the GT rest when an engine reset failure is received to break
this circular dependency.

v2:
 (John Harrison)
  - Store engine reset mask
  - Fix typo in commit message
v3:
 (John Harrison)
  - Fix another typo in commit message
  - s/reset_*/reset_fail_*/

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220121043118.24886-3-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 9d26a86..d59bbf4 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -119,6 +119,15 @@ struct intel_guc {
                 * function as it might be in an atomic context (no sleeping)
                 */
                struct work_struct destroyed_worker;
+               /**
+                * @reset_fail_worker: worker to trigger a GT reset after an
+                * engine reset fails
+                */
+               struct work_struct reset_fail_worker;
+               /**
+                * @reset_fail_mask: mask of engines that failed to reset
+                */
+               intel_engine_mask_t reset_fail_mask;
        } submission_state;
 
        /**

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index 411054f..6fc73f2 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1730,6 +1730,7 @@ void intel_guc_submission_reset_finish(struct intel_guc *guc)
 }
 
 static void destroyed_worker_func(struct work_struct *w);
+static void reset_fail_worker_func(struct work_struct *w);
 
 /*
  * Set up the memory resources to be shared with the GuC (via the GGTT)
@@ -1760,6 +1761,8 @@ int intel_guc_submission_init(struct intel_guc *guc)
        INIT_LIST_HEAD(&guc->submission_state.destroyed_contexts);
        INIT_WORK(&guc->submission_state.destroyed_worker,
                  destroyed_worker_func);
+       INIT_WORK(&guc->submission_state.reset_fail_worker,
+                 reset_fail_worker_func);
 
        guc->submission_state.guc_ids_bitmap =
                bitmap_zalloc(NUMBER_MULTI_LRC_GUC_ID(guc), GFP_KERNEL);
@@ -4025,6 +4028,26 @@ guc_lookup_engine(struct intel_guc *guc, u8 guc_class, u8 instance)
        return gt->engine_class[engine_class][instance];
 }
 
+static void reset_fail_worker_func(struct work_struct *w)
+{
+       struct intel_guc *guc = container_of(w, struct intel_guc,
+                                            submission_state.reset_fail_worker);
+       struct intel_gt *gt = guc_to_gt(guc);
+       intel_engine_mask_t reset_fail_mask;
+       unsigned long flags;
+
+       spin_lock_irqsave(&guc->submission_state.lock, flags);
+       reset_fail_mask = guc->submission_state.reset_fail_mask;
+       guc->submission_state.reset_fail_mask = 0;
+       spin_unlock_irqrestore(&guc->submission_state.lock, flags);
+
+       if (likely(reset_fail_mask))
+               intel_gt_handle_error(gt, reset_fail_mask,
+                                     I915_ERROR_CAPTURE,
+                                     "GuC failed to reset engine mask=0x%x\n",
+                                     reset_fail_mask);
+}
+
 int intel_guc_engine_failure_process_msg(struct intel_guc *guc,
                                         const u32 *msg, u32 len)
 {
@@ -4032,6 +4055,7 @@ int intel_guc_engine_failure_process_msg(struct intel_guc *guc,
        struct intel_gt *gt = guc_to_gt(guc);
        u8 guc_class, instance;
        u32 reason;
+       unsigned long flags;
 
        if (unlikely(len != 3)) {
                drm_err(&gt->i915->drm, "Invalid length %u", len);
@@ -4056,10 +4080,15 @@ int intel_guc_engine_failure_process_msg(struct intel_guc *guc,
        drm_err(&gt->i915->drm, "GuC engine reset request failed on %d:%d (%s) because 0x%08X",
                guc_class, instance, engine->name, reason);
 
-       intel_gt_handle_error(gt, engine->mask,
-                             I915_ERROR_CAPTURE,
-                             "GuC failed to reset %s (reason=0x%08x)\n",
-                             engine->name, reason);
+       spin_lock_irqsave(&guc->submission_state.lock, flags);
+       guc->submission_state.reset_fail_mask |= engine->mask;
+       spin_unlock_irqrestore(&guc->submission_state.lock, flags);
+
+       /*
+        * A GT reset flushes this worker queue (G2H handler) so we must use
+        * another worker to trigger a GT reset.
+        */
+       queue_work(system_unbound_wq, &guc->submission_state.reset_fail_worker);
 
        return 0;
 }