Messages in this thread | | | Subject | Re: [PATCH 1/7] drm/bridge: Support hotplugging panel-bridge. | From | Archit Taneja <> | Date | Fri, 16 Jun 2017 11:13:01 +0530 |
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On 06/16/2017 02:11 AM, Eric Anholt wrote: > If the panel-bridge is being set up after the drm_mode_config_reset(), > then the connector's state would never get initialized, and we'd > dereference the NULL in the hotplug path. We also need to register > the connector, so that userspace can get at it. >
Shouldn't the KMS driver make sure the panel-bridge is set up before drm_mode_config_reset? Is it the case when we're inserting the panel-bridge driver as a module?
All the connectors that have been added are registered automatically when drm_dev_register() is called by the KMS driver. Registering a connector in the middle of setting up our driver is prone to race conditions if the userspace decides to use them immediately.
Thanks, Archit
> Signed-off-by: Eric Anholt <eric@anholt.net> > --- > drivers/gpu/drm/bridge/panel.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c > index 67fe19e5a9c6..8ed8a70799c7 100644 > --- a/drivers/gpu/drm/bridge/panel.c > +++ b/drivers/gpu/drm/bridge/panel.c > @@ -82,11 +82,14 @@ static int panel_bridge_attach(struct drm_bridge *bridge) > > drm_mode_connector_attach_encoder(&panel_bridge->connector, > bridge->encoder); > + drm_atomic_helper_connector_reset(&panel_bridge->connector); > > ret = drm_panel_attach(panel_bridge->panel, &panel_bridge->connector); > if (ret < 0) > return ret; > > + drm_connector_register(&panel_bridge->connector); > + > return 0; > } > >
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