drm/i915/gt: Exercise lrc_wa_ctx initialisation failure

Inject a fault into lrc_init_wa_ctx() to ensure that we can tolerate a
failure to construct the workarounds.

v2: Avoid mentioning an error for fault-injection, other CI will
complain about the dmesg spam.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210109114453.27798-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
index d857d16..4d7ac81 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
@@ -3244,13 +3244,7 @@ int intel_execlists_submission_setup(struct intel_engine_cs *engine)
        if (engine->class == RENDER_CLASS)
                rcs_submission_override(engine);
 
-       if (lrc_init_wa_ctx(engine))
-               /*
-                * We continue even if we fail to initialize WA batch
-                * because we only expect rare glitches but nothing
-                * critical to prevent us from using GPU
-                */
-               drm_err(&i915->drm, "WA batch buffer initialization failed\n");
+       lrc_init_wa_ctx(engine);
 
        if (HAS_LOGICAL_RING_ELSQ(i915)) {
                execlists->submit_reg = uncore->regs +

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 703d9ec..7956cda 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1460,7 +1460,7 @@ void lrc_fini_wa_ctx(struct intel_engine_cs *engine)
 
 typedef u32 *(*wa_bb_func_t)(struct intel_engine_cs *engine, u32 *batch);
 
-int lrc_init_wa_ctx(struct intel_engine_cs *engine)
+void lrc_init_wa_ctx(struct intel_engine_cs *engine)
 {
        struct i915_ctx_workarounds *wa_ctx = &engine->wa_ctx;
        struct i915_wa_ctx_bb *wa_bb[] = {
@@ -1469,15 +1469,15 @@ int lrc_init_wa_ctx(struct intel_engine_cs *engine)
        wa_bb_func_t wa_bb_fn[ARRAY_SIZE(wa_bb)];
        void *batch, *batch_ptr;
        unsigned int i;
-       int ret;
+       int err;
 
        if (engine->class != RENDER_CLASS)
-               return 0;
+               return;
 
        switch (INTEL_GEN(engine->i915)) {
        case 12:
        case 11:
-               return 0;
+               return;
        case 10:
                wa_bb_fn[0] = gen10_init_indirectctx_bb;
                wa_bb_fn[1] = NULL;
@@ -1492,14 +1492,20 @@ int lrc_init_wa_ctx(struct intel_engine_cs *engine)
                break;
        default:
                MISSING_CASE(INTEL_GEN(engine->i915));
-               return 0;
+               return;
        }
 
-       ret = lrc_setup_wa_ctx(engine);
-       if (ret) {
-               drm_dbg(&engine->i915->drm,
-                       "Failed to setup context WA page: %d\n", ret);
-               return ret;
+       err = lrc_setup_wa_ctx(engine);
+       if (err) {
+               /*
+                * We continue even if we fail to initialize WA batch
+                * because we only expect rare glitches but nothing
+                * critical to prevent us from using GPU
+                */
+               drm_err(&engine->i915->drm,
+                       "Ignoring context switch w/a allocation error:%d\n",
+                       err);
+               return;
        }
 
        batch = i915_gem_object_pin_map(wa_ctx->vma->obj, I915_MAP_WB);
@@ -1514,7 +1520,7 @@ int lrc_init_wa_ctx(struct intel_engine_cs *engine)
                wa_bb[i]->offset = batch_ptr - batch;
                if (GEM_DEBUG_WARN_ON(!IS_ALIGNED(wa_bb[i]->offset,
                                                  CACHELINE_BYTES))) {
-                       ret = -EINVAL;
+                       err = -EINVAL;
                        break;
                }
                if (wa_bb_fn[i])
@@ -1525,10 +1531,10 @@ int lrc_init_wa_ctx(struct intel_engine_cs *engine)
 
        __i915_gem_object_flush_map(wa_ctx->vma->obj, 0, batch_ptr - batch);
        __i915_gem_object_release_map(wa_ctx->vma->obj);
-       if (ret)
-               lrc_fini_wa_ctx(engine);
 
-       return ret;
+       /* Verify that we can handle failure to setup the wa_ctx */
+       if (err || i915_inject_probe_error(engine->i915, -ENODEV))
+               lrc_fini_wa_ctx(engine);
 }
 
 static void st_update_runtime_underflow(struct intel_context *ce, s32 dt)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.h b/drivers/gpu/drm/i915/gt/intel_lrc.h
index 4e00685..7f69784 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_lrc.h
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.h
@@ -26,7 +26,7 @@ struct intel_ring;
 #define LRC_PPHWSP_SCRATCH             0x34
 #define LRC_PPHWSP_SCRATCH_ADDR                (LRC_PPHWSP_SCRATCH * sizeof(u32))
 
-int lrc_init_wa_ctx(struct intel_engine_cs *engine);
+void lrc_init_wa_ctx(struct intel_engine_cs *engine);
 void lrc_fini_wa_ctx(struct intel_engine_cs *engine);
 
 int lrc_alloc(struct intel_context *ce,