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drm: Don't race connector registration 

[ Upstream commit e6e7b48b29 ]

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>
steinar/wifi_calib_4_9_kernel
Daniel Vetter 2017-01-12 17:15:56 +01:00 committed by Greg Kroah-Hartman
parent 82b6693bd4
commit 326fdffd70
3 changed files with 8 additions and 0 deletions
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3
drivers/gpu/drm/drm_connector.c
View File

@ -379,6 +379,9 @@ int drm_connector_register(struct drm_connector *connector)
{
int ret = 0;
if (!connector->dev->registered)
return 0;
mutex_lock(&connector->mutex);
if (connector->registered)
goto unlock;

4
drivers/gpu/drm/drm_drv.c
View File

@ -710,6 +710,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
if (ret)
goto err_minors;
dev->registered = true;
if (dev->driver->load) {
ret = dev->driver->load(dev, flags);
if (ret)
@ -749,6 +751,8 @@ void drm_dev_unregister(struct drm_device *dev)
drm_lastclose(dev);
dev->registered = false;
if (drm_core_check_feature(dev, DRIVER_MODESET))
drm_modeset_unregister_all(dev);

1
include/drm/drmP.h
View File

@ -776,6 +776,7 @@ struct drm_device {
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;