drm: remove drm_bridge_hpd_disable() from drm_bridge_connector_destroy()

drm_bridge_hpd_enable()/drm_bridge_hpd_disable() callbacks call into
the respective driver's hpd_enable()/hpd_disable() ops. These ops control
the HPD enable/disable logic which in some cases like MSM can be a
dedicate hardware block to control the HPD.

During probe_defer cases, a connector can be initialized and then later
destroyed till the probe is retried. During connector destroy in these
cases, the hpd_disable() callback gets called without a corresponding
hpd_enable() leading to an unbalanced state potentially causing even
a crash.

This can be avoided by the respective drivers maintaining their own
state logic to ensure that a hpd_disable() without a corresponding
hpd_enable() just returns without doing anything.

However, to have a generic fix it would be better to avoid the
hpd_disable() callback from the connector destroy path and let
the hpd_enable() / hpd_disable() balance be maintained by the
corresponding drm_bridge_connector_enable_hpd() /
drm_bridge_connector_disable_hpd() APIs which should get called by
drm_kms_helper_disable_hpd().

changes in v2:
	- minor change in commit text (Dmitry)

Signed-off-by: Abhinav Kumar <[email protected]>
Reviewed-by: Dmitry Baryshkov <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Signed-off-by: Dmitry Baryshkov <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: Abhinav Kumar

drivers/gpu/drm/drm_bridge_connector.c

@@ -198,12 +198,6 @@ static void drm_bridge_connector_destroy(struct drm_connector *connector)
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
 
-	if (bridge_connector->bridge_hpd) {
-		struct drm_bridge *hpd = bridge_connector->bridge_hpd;
-
-		drm_bridge_hpd_disable(hpd);
-	}
-
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);