drm/i915: Hold rpm wakeref for debugfs/i915_drop_caches_set

Since we peek into HW state and poke around, it behoves us to acquire a
runtime pm wakeref beforehand.

References: https://bugs.freedesktop.org/show_bug.cgi?id=108343
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108364
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181015115856.18590-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 7b7f844..5f3c639 100644 (file)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4187,6 +4187,7 @@ i915_drop_caches_set(void *data, u64 val)
 
        DRM_DEBUG("Dropping caches: 0x%08llx [0x%08llx]\n",
                  val, val & DROP_ALL);
+       intel_runtime_pm_get(i915);
 
        if (val & DROP_RESET_ACTIVE && !intel_engines_are_idle(i915))
                i915_gem_set_wedged(i915);
@@ -4204,11 +4205,8 @@ i915_drop_caches_set(void *data, u64 val)
                                                     I915_WAIT_LOCKED,
                                                     MAX_SCHEDULE_TIMEOUT);
 
-               if (ret == 0 && val & DROP_RESET_SEQNO) {
-                       intel_runtime_pm_get(i915);
+               if (ret == 0 && val & DROP_RESET_SEQNO)
                        ret = i915_gem_set_global_seqno(&i915->drm, 1);
-                       intel_runtime_pm_put(i915);
-               }
 
                if (val & DROP_RETIRE)
                        i915_retire_requests(i915);
@@ -4246,6 +4244,8 @@ i915_drop_caches_set(void *data, u64 val)
        if (val & DROP_FREED)
                i915_gem_drain_freed_objects(i915);
 
+       intel_runtime_pm_put(i915);
+
        return ret;
 }