When we wedge the device, we override engine->submit_request with a nop
to ensure that all in-flight requests are marked in error. However, igt
would like to unwedge the device to test -EIO handling. This requires us
to flush those in-flight requests and restore the original
engine->submit_request.
v2: Use a vfunc to unify enabling request submission to engines
v3: Split new vfunc to a separate patch.
Fixes: 821ed7df6e2a ("drm/i915: Update reset path to fix incomplete requests")
Testcase: igt/gem_eio
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.c | 2 +-
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem.c | 51 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 53 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e312b61ba6bb..11d1066b673c 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1822,7 +1822,7 @@ void i915_reset(struct drm_i915_private *dev_priv)
return;
/* Clear any previous failed attempts at recovery. Time to try again. */
- __clear_bit(I915_WEDGED, &error->flags);
+ i915_gem_unset_wedged(dev_priv);
error->reset_count++;
pr_notice("drm/i915: Resetting chip after gpu hang\n");
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 48ff64812289..53a791d8d992 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3406,6 +3406,7 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv);
void i915_gem_reset(struct drm_i915_private *dev_priv);
void i915_gem_reset_finish(struct drm_i915_private *dev_priv);
void i915_gem_set_wedged(struct drm_i915_private *dev_priv);
+void i915_gem_unset_wedged(struct drm_i915_private *dev_priv);
void i915_gem_init_mmio(struct drm_i915_private *i915);
int __must_check i915_gem_init(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 202bb850f260..e06830916a05 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3000,6 +3000,57 @@ void i915_gem_set_wedged(struct drm_i915_private *dev_priv)
mod_delayed_work(dev_priv->wq, &dev_priv->gt.idle_work, 0);
}
+void i915_gem_unset_wedged(struct drm_i915_private *i915)
+{
+ struct i915_gem_timeline *tl;
+ int i;
+
+ lockdep_assert_held(&i915->drm.struct_mutex);
+ if (!test_bit(I915_WEDGED, &i915->gpu_error.flags))
+ return;
+
+ /* Before unwedging, make sure that all pending operations
+ * are flushed and errored out. No more can be submitted until
+ * we reset the wedged bit.
+ */
+ list_for_each_entry(tl, &i915->gt.timelines, link) {
+ for (i = 0; i < ARRAY_SIZE(tl->engine); i++) {
+ struct drm_i915_gem_request *rq;
+
+ rq = i915_gem_active_peek(&tl->engine[i].last_request,
+ &i915->drm.struct_mutex);
+ if (!rq)
+ continue;
+
+ /* We can't use our normal waiter as we want to
+ * avoid recursively trying to handle the current
+ * reset. The basic dma_fence_default_wait() installs
+ * a callback for dma_fence_signal(), which is
+ * triggered by our nop handler (indirectly, the
+ * callback enables the signaler thread which is
+ * woken by the nop_submit_request() advancing the seqno
+ * and when the seqno passes the fence, the signaler
+ * then signals the fence waking us up).
+ */
+ dma_fence_default_wait(&rq->fence, false,
+ MAX_SCHEDULE_TIMEOUT);
+ }
+ }
+
+ /* Undo nop_submit_request. We prevent all new i915 requests from
+ * being queued (by disallowing execbuf whilst wedged) so having
+ * waited for all active requests above, we know the system is idle
+ * and do not have to worry about a thread being inside
+ * engine->submit_request() as we swap over. So unlike installing
+ * the nop_submit_request on reset, we can do this from normal
+ * context and do not require stop_machine().
+ */
+ intel_engines_enable_submission(i915);
+
+ smp_mb__before_atomic(); /* complete takeover before enabling execbuf */
+ clear_bit(I915_WEDGED, &i915->gpu_error.flags);
+}
+
static void
i915_gem_retire_work_handler(struct work_struct *work)
{
--
2.11.0
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