@@ -1752,6 +1752,8 @@ int i915_resume_switcheroo(struct drm_device *dev)
* Reset the chip. Useful if a hang is detected. Returns zero on successful
* reset or otherwise an error code.
*
+ * Caller must hold the struct_mutex.
+ *
* Procedure is fairly simple:
* - reset the chip using the reset reg
* - re-init context state
@@ -1766,7 +1768,10 @@ int i915_reset(struct drm_i915_private *dev_priv)
struct i915_gpu_error *error = &dev_priv->gpu_error;
int ret;
- mutex_lock(&dev->struct_mutex);
+ lockdep_assert_held(&dev->struct_mutex);
+
+ if (!test_and_clear_bit(I915_RESET_IN_PROGRESS, &error->flags))
+ return 0;
/* Clear any previous failed attempts at recovery. Time to try again. */
__clear_bit(I915_WEDGED, &error->flags);
@@ -1807,9 +1812,6 @@ int i915_reset(struct drm_i915_private *dev_priv)
goto error;
}
- clear_bit(I915_RESET_IN_PROGRESS, &error->flags);
- mutex_unlock(&dev->struct_mutex);
-
/*
* rps/rc6 re-init is necessary to restore state lost after the
* reset and the re-install of gt irqs. Skip for ironlake per
@@ -1823,7 +1825,6 @@ int i915_reset(struct drm_i915_private *dev_priv)
error:
set_bit(I915_WEDGED, &error->flags);
- mutex_unlock(&dev->struct_mutex);
return ret;
}
@@ -3849,7 +3849,9 @@ wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
schedule_timeout_uninterruptible(remaining_jiffies);
}
}
-static inline bool __i915_request_irq_complete(struct drm_i915_gem_request *req)
+
+static inline bool
+__i915_request_irq_complete(struct drm_i915_gem_request *req)
{
struct intel_engine_cs *engine = req->engine;
@@ -3911,17 +3913,6 @@ static inline bool __i915_request_irq_complete(struct drm_i915_gem_request *req)
return true;
}
- /* We need to check whether any gpu reset happened in between
- * the request being submitted and now. If a reset has occurred,
- * the seqno will have been advance past ours and our request
- * is complete. If we are in the process of handling a reset,
- * the request is effectively complete as the rendering will
- * be discarded, but we need to return in order to drop the
- * struct_mutex.
- */
- if (i915_reset_in_progress(&req->i915->gpu_error))
- return true;
-
return false;
}
@@ -2800,7 +2800,8 @@ __i915_gem_object_sync(struct drm_i915_gem_request *to,
if (!i915.semaphores) {
ret = i915_wait_request(from,
- from->i915->mm.interruptible,
+ from->i915->mm.interruptible |
+ I915_WAIT_LOCKED,
NULL,
NO_WAITBOOST);
if (ret)
@@ -666,8 +666,8 @@ int i915_wait_request(struct drm_i915_gem_request *req,
if (i915_spin_request(req, state, 5))
goto complete;
- set_current_state(state);
- add_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
+ if (flags & I915_WAIT_LOCKED)
+ add_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
intel_wait_init(&wait, req->fence.seqno);
if (intel_engine_add_wait(req->engine, &wait))
@@ -692,9 +692,9 @@ int i915_wait_request(struct drm_i915_gem_request *req,
if (intel_wait_complete(&wait))
break;
+wakeup:
set_current_state(state);
-wakeup:
/* Carefully check if the request is complete, giving time
* for the seqno to be visible following the interrupt.
* We also have to check in case we are kicked by the GPU
@@ -703,11 +703,32 @@ wakeup:
if (__i915_request_irq_complete(req))
break;
+ /* If the GPU is hung, and we hold the lock, reset the GPU
+ * and then check for completion. On a full reset, the engine's
+ * HW seqno will be advanced passed us and we are complete.
+ * If we do a partial reset, we have to wait for the GPU to
+ * resume and update the breadcrumb.
+ *
+ * If we don't hold the mutex, we can just wait for the worker
+ * to come along and update the breadcrumb (either directly
+ * itself, or indirectly by recovering the GPU).
+ */
+ if (flags & I915_WAIT_LOCKED &&
+ i915_reset_in_progress(&req->i915->gpu_error)) {
+ __set_current_state(TASK_RUNNING);
+ if (!i915_reset(req->i915))
+ goto wakeup;
+
+ break;
+ }
+
/* Only spin if we know the GPU is processing this request */
if (i915_spin_request(req, state, 2))
break;
}
- remove_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
+
+ if (flags & I915_WAIT_LOCKED)
+ remove_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
intel_engine_remove_wait(req->engine, &wait);
__set_current_state(TASK_RUNNING);
@@ -223,6 +223,7 @@ int i915_wait_request(struct drm_i915_gem_request *req,
struct intel_rps_client *rps)
__attribute__((nonnull(1)));
#define I915_WAIT_INTERRUPTIBLE BIT(0)
+#define I915_WAIT_LOCKED BIT(1) /* struct_mutex held, handle GPU reset */
static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine);
@@ -576,7 +577,9 @@ i915_gem_active_wait(const struct i915_gem_active *active, struct mutex *mutex)
if (!request)
return 0;
- return i915_wait_request(request, I915_WAIT_INTERRUPTIBLE, NULL, NULL);
+ return i915_wait_request(request,
+ I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
+ NULL, NULL);
}
/**
@@ -639,7 +642,9 @@ i915_gem_active_retire(struct i915_gem_active *active,
if (!request)
return 0;
- ret = i915_wait_request(request, I915_WAIT_INTERRUPTIBLE, NULL, NULL);
+ ret = i915_wait_request(request,
+ I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
+ NULL, NULL);
if (ret)
return ret;
@@ -2521,7 +2521,9 @@ static void i915_reset_and_wakeup(struct drm_i915_private *dev_priv)
* pending state and not properly drop locks, resulting in
* deadlocks with the reset work.
*/
+ mutex_lock(&dev_priv->drm.struct_mutex);
ret = i915_reset(dev_priv);
+ mutex_unlock(&dev_priv->drm.struct_mutex);
intel_finish_reset(dev_priv);
@@ -2223,14 +2223,12 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
if (WARN_ON(&target->ring_link == &ring->request_list))
return -ENOSPC;
- ret = i915_wait_request(target, I915_WAIT_INTERRUPTIBLE,
+ ret = i915_wait_request(target,
+ I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
NULL, NO_WAITBOOST);
if (ret)
return ret;
- if (i915_reset_in_progress(&target->i915->gpu_error))
- return -EAGAIN;
-
i915_gem_request_retire_upto(target);
intel_ring_update_space(ring);
If a waiter is holding the struct_mutex, then the reset worker cannot reset the GPU until the waiter returns. We do not want to return -EAGAIN form i915_wait_request as that breaks delicate operations like i915_vma_unbind() which often cannot be restarted easily, and returning -EIO is just as useless (and has in the past proven dangerous). The remaining WARN_ON(i915_wait_request) serve as a valuable reminder that handling errors from an indefinite wait are tricky. We can keep the current semantic that knowing after a reset is complete, so is the request, by performing the reset ourselves if we hold the mutex. uevent emission is still handled by the reset worker, so it may appear slightly out of order with respect to the actual reset (and concurrent use of the device). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/gpu/drm/i915/i915_drv.c | 11 ++++++----- drivers/gpu/drm/i915/i915_drv.h | 15 +++------------ drivers/gpu/drm/i915/i915_gem.c | 3 ++- drivers/gpu/drm/i915/i915_gem_request.c | 29 +++++++++++++++++++++++++---- drivers/gpu/drm/i915/i915_gem_request.h | 9 +++++++-- drivers/gpu/drm/i915/i915_irq.c | 2 ++ drivers/gpu/drm/i915/intel_ringbuffer.c | 6 ++---- 7 files changed, 47 insertions(+), 28 deletions(-)