Unfortunately since we don't have Dave's connector refcounting patch
here yet, it's very possible that drm_atomic_state_default_clear() could
get called by intel_display_resume() when
intel_dp_mst_destroy_connector() isn't completely finished destroying an
mst connector, but has already finished setting connector->funcs to
NULL. As such, we need to treat the connector like it's already been
destroyed and just skip it, otherwise we'll end up dereferencing a NULL
pointer.
This fix is only required for 4.6 and below. David Airlie's patchseries
for 4.7 to add connector reference counting provides a more proper fix
for this.
Upstream fix: b164d31f50b2923a7a92c2a40cb46973a6ba8c36
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Lyude <cpaul@xxxxxxxxxx>
---
drivers/gpu/drm/drm_atomic.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 8ee1db8..d3a5b5c 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -139,7 +139,7 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
for (i = 0; i < state->num_connector; i++) {
struct drm_connector *connector = state->connectors[i];
- if (!connector)
+ if (!connector || !connector->funcs)
continue;
/*
@@ -150,6 +150,7 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
* case by setting all connector pointers to NULL.
*/
state->connector_states[i]->connector = NULL;
+
connector->funcs->atomic_destroy_state(NULL,
state->connector_states[i]);
state->connectors[i] = NULL;
--
2.5.5
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