It's true we can't resume the device from poll workers in
nouveau_connector_detect(). We can however, prevent the autosuspend
timer from elapsing immediately if it hasn't already without risking any
sort of deadlock with the runtime suspend/resume operations. So do that
instead of entirely avoiding grabbing a power reference.

Signed-off-by: Lyude Paul <ly...@redhat.com>
Cc: sta...@vger.kernel.org
Cc: Lukas Wunner <lu...@wunner.de>
Cc: Karol Herbst <karolher...@gmail.com>
---
 drivers/gpu/drm/nouveau/nouveau_connector.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c 
b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 2a45b4c2ceb0..010d6db14cba 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -572,12 +572,16 @@ nouveau_connector_detect(struct drm_connector *connector, 
bool force)
                nv_connector->edid = NULL;
        }
 
-       /* Outputs are only polled while runtime active, so acquiring a
-        * runtime PM ref here is unnecessary (and would deadlock upon
-        * runtime suspend because it waits for polling to finish).
+       /* Outputs are only polled while runtime active, so resuming the
+        * device here is unnecessary (and would deadlock upon runtime suspend
+        * because it waits for polling to finish). We do however, want to
+        * prevent the autosuspend timer from elapsing during this operation
+        * if possible.
         */
-       if (!drm_kms_helper_is_poll_worker()) {
-               ret = pm_runtime_get_sync(connector->dev->dev);
+       if (drm_kms_helper_is_poll_worker()) {
+               pm_runtime_get_noresume(dev->dev);
+       } else {
+               ret = pm_runtime_get_sync(dev->dev);
                if (ret < 0 && ret != -EACCES)
                        return conn_status;
        }
@@ -655,10 +659,8 @@ nouveau_connector_detect(struct drm_connector *connector, 
bool force)
 
  out:
 
-       if (!drm_kms_helper_is_poll_worker()) {
-               pm_runtime_mark_last_busy(connector->dev->dev);
-               pm_runtime_put_autosuspend(connector->dev->dev);
-       }
+       pm_runtime_mark_last_busy(dev->dev);
+       pm_runtime_put_autosuspend(dev->dev);
 
        return conn_status;
 }
-- 
2.17.1

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