drm/i915: Flush idle work when changing missed-irq fault injection

In order for the missed-irq update to take effect, the device must be
idle. So when the user updates the fault injection via debugfs, idle the
device.

v2: Idle is explicitly required for setting test_irq, and good behaviour
for clearing the missed_irq.
v3: Use matching types; expanding to more than ulong rings is left as an
exercise to the reader.

Testcase: igt/drv_missed_irq
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170307155908.14576-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 478f19d..3234020 100644 (file)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4151,6 +4151,41 @@ DEFINE_SIMPLE_ATTRIBUTE(i915_wedged_fops,
                        "%llu\n");
 
 static int
+fault_irq_set(struct drm_i915_private *i915,
+             unsigned long *irq,
+             unsigned long val)
+{
+       int err;
+
+       err = mutex_lock_interruptible(&i915->drm.struct_mutex);
+       if (err)
+               return err;
+
+       err = i915_gem_wait_for_idle(i915,
+                                    I915_WAIT_LOCKED |
+                                    I915_WAIT_INTERRUPTIBLE);
+       if (err)
+               goto err_unlock;
+
+       /* Retire to kick idle work */
+       i915_gem_retire_requests(i915);
+       GEM_BUG_ON(i915->gt.active_requests);
+
+       *irq = val;
+       mutex_unlock(&i915->drm.struct_mutex);
+
+       /* Flush idle worker to disarm irq */
+       while (flush_delayed_work(&i915->gt.idle_work))
+               ;
+
+       return 0;
+
+err_unlock:
+       mutex_unlock(&i915->drm.struct_mutex);
+       return err;
+}
+
+static int
 i915_ring_missed_irq_get(void *data, u64 *val)
 {
        struct drm_i915_private *dev_priv = data;
@@ -4162,18 +4197,9 @@ i915_ring_missed_irq_get(void *data, u64 *val)
 static int
 i915_ring_missed_irq_set(void *data, u64 val)
 {
-       struct drm_i915_private *dev_priv = data;
-       struct drm_device *dev = &dev_priv->drm;
-       int ret;
+       struct drm_i915_private *i915 = data;
 
-       /* Lock against concurrent debugfs callers */
-       ret = mutex_lock_interruptible(&dev->struct_mutex);
-       if (ret)
-               return ret;
-       dev_priv->gpu_error.missed_irq_rings = val;
-       mutex_unlock(&dev->struct_mutex);
-
-       return 0;
+       return fault_irq_set(i915, &i915->gpu_error.missed_irq_rings, val);
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(i915_ring_missed_irq_fops,
@@ -4193,13 +4219,12 @@ i915_ring_test_irq_get(void *data, u64 *val)
 static int
 i915_ring_test_irq_set(void *data, u64 val)
 {
-       struct drm_i915_private *dev_priv = data;
+       struct drm_i915_private *i915 = data;
 
-       val &= INTEL_INFO(dev_priv)->ring_mask;
+       val &= INTEL_INFO(i915)->ring_mask;
        DRM_DEBUG_DRIVER("Masking interrupts on rings 0x%08llx\n", val);
-       dev_priv->gpu_error.test_irq_rings = val;
 
-       return 0;
+       return fault_irq_set(i915, &i915->gpu_error.test_irq_rings, val);
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(i915_ring_test_irq_fops,