On 2019-08-20 12:16 p.m., Ville Syrjala wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
We're not allowed to create new properties after device registration so for MST connectors we need to either create the max_bpc property earlier, or we reuse one we already have. Let's do the latter apporach since the corresponding SST connector already has the prop and its min/max are correct also for the MST connector.
The problem was highlighted by commit 4f5368b5541a ("drm/kms: Catch mode_object lifetime errors") which results in the following spew: [ 1330.878941] WARNING: CPU: 2 PID: 1554 at drivers/gpu/drm/drm_mode_object.c:45 __drm_mode_object_add+0xa0/0xb0 [drm] ... [ 1330.879008] Call Trace: [ 1330.879023] drm_property_create+0xba/0x180 [drm] [ 1330.879036] drm_property_create_range+0x15/0x30 [drm] [ 1330.879048] drm_connector_attach_max_bpc_property+0x62/0x80 [drm] [ 1330.879086] intel_dp_add_mst_connector+0x11f/0x140 [i915] [ 1330.879094] drm_dp_add_port.isra.20+0x20b/0x440 [drm_kms_helper] ...
Cc: stable@vger.kernel.org Cc: Lyude Paul lyude@redhat.com Cc: sunpeng.li@amd.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Sean Paul sean@poorly.run Fixes: 5ca0ef8a56b8 ("drm/i915: Add max_bpc property for DP MST") Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
Thanks for following up, I had forgotten about this issue. Reviewed-by: Leo Li sunpeng.li@amd.com
drivers/gpu/drm/i915/display/intel_dp_mst.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 83faa246e361..9748581c1d62 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -536,7 +536,15 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo intel_attach_force_audio_property(connector); intel_attach_broadcast_rgb_property(connector);
- drm_connector_attach_max_bpc_property(connector, 6, 12);
- /*
* Reuse the prop from the SST connector because we're* not allowed to create new props after device registration.*/- connector->max_bpc_property =
intel_dp->attached_connector->base.max_bpc_property;- if (connector->max_bpc_property)
drm_connector_attach_max_bpc_property(connector, 6, 12);return connector;