4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Lyude Paul <lyude@xxxxxxxxxx>
commit d77ef138ff572409ab93d492e5e6c826ee6fb21d upstream.
Turns out this part is my fault for not noticing when reviewing
9a2eba337cace ("drm/nouveau: Fix drm poll_helper handling"). Currently
we call drm_kms_helper_poll_enable() from nouveau_display_hpd_work().
This makes basically no sense however, because that means we're calling
drm_kms_helper_poll_enable() every time we schedule the hotplug
detection work. This is also against the advice mentioned in
drm_kms_helper_poll_enable()'s documentation:
Note that calls to enable and disable polling must be strictly ordered,
which is automatically the case when they're only call from
suspend/resume callbacks.
Of course, hotplugs can't really be ordered. They could even happen
immediately after we called drm_kms_helper_poll_disable() in
nouveau_display_fini(), which can lead to all sorts of issues.
Additionally; enabling polling /after/ we call
drm_helper_hpd_irq_event() could also mean that we'd miss a hotplug
event anyway, since drm_helper_hpd_irq_event() wouldn't bother trying to
probe connectors so long as polling is disabled.
So; simply move this back into nouveau_display_init() again. The race
condition that both of these patches attempted to work around has
already been fixed properly in
d61a5c106351 ("drm/nouveau: Fix deadlock on runtime suspend")
Fixes: 9a2eba337cace ("drm/nouveau: Fix drm poll_helper handling")
Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
Acked-by: Karol Herbst <kherbst@xxxxxxxxxx>
Acked-by: Daniel Vetter <daniel@xxxxxxxx>
Cc: Lukas Wunner <lukas@xxxxxxxxx>
Cc: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/nouveau/nouveau_display.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/nouveau/nouveau_display.c
+++ b/drivers/gpu/drm/nouveau/nouveau_display.c
@@ -356,8 +356,6 @@ nouveau_display_hpd_work(struct work_str
pm_runtime_get_sync(drm->dev->dev);
drm_helper_hpd_irq_event(drm->dev);
- /* enable polling for external displays */
- drm_kms_helper_poll_enable(drm->dev);
pm_runtime_mark_last_busy(drm->dev->dev);
pm_runtime_put_sync(drm->dev->dev);
@@ -412,6 +410,11 @@ nouveau_display_init(struct drm_device *
if (ret)
return ret;
+ /* enable connector detection and polling for connectors without HPD
+ * support
+ */
+ drm_kms_helper_poll_enable(dev);
+
/* enable hotplug interrupts */
drm_connector_list_iter_begin(dev, &conn_iter);
nouveau_for_each_non_mst_connector_iter(connector, &conn_iter) {
