drm: Don't race connector registration
[ Upstream commit e6e7b48b295afa5a5ab440de0a94d9ad8b3ce2d0 ]
I was under the misconception that the sysfs dev stuff can be fully
set up, and then registered all in one step with device_add. That's
true for properties and property groups, but not for parents and child
devices. Those must be fully registered before you can register a
child.
Add a bit of tracking to make sure that asynchronous mst connector
hotplugging gets this right. For consistency we rely upon the implicit
barriers of the connector->mutex, which is taken anyway, to ensure
that at least either the connector or device registration call will
work out.
Mildly tested since I can't reliably reproduce this on my mst box
here.
Reported-by: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1484237756-2720-1-git-send-email-daniel.vetter@ffwll.ch
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index a103f1f..0e934a9 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -379,6 +379,9 @@
{
int ret = 0;
+ if (!connector->dev->registered)
+ return 0;
+
mutex_lock(&connector->mutex);
if (connector->registered)
goto unlock;
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 0f2fa90..362b8cd 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -710,6 +710,8 @@
if (ret)
goto err_minors;
+ dev->registered = true;
+
if (dev->driver->load) {
ret = dev->driver->load(dev, flags);
if (ret)
@@ -749,6 +751,8 @@
drm_lastclose(dev);
+ dev->registered = false;
+
if (drm_core_check_feature(dev, DRIVER_MODESET))
drm_modeset_unregister_all(dev);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index e9fb2e8..0c4f9c67 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -776,6 +776,7 @@
struct drm_minor *control; /**< Control node */
struct drm_minor *primary; /**< Primary node */
struct drm_minor *render; /**< Render node */
+ bool registered;
/* currently active master for this device. Protected by master_mutex */
struct drm_master *master;