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drm/fbdev-helper: Grab mode_config.mutex in drm_fb_helper_single_add_all_connectors

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This is now truly only duct-tape to keep locking checks happy since
calling this function when hpd or polling are already enabled is a
bug. The fbdev helper can't cope with hotplug changes yet at this
point, only after that.

Otoh a bit more robustness in this function can't hurt, and with this
fbdev can actually cope with hotplug changes. And it's also more
consistent with the connector hotadd/remove dp mst needs to do.
Therefore document this as new official behavior.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
This commit is contained in:
Daniel Vetter 2015-07-09 23:44:27 +02:00
parent 8c4ccc4ab6
commit 169faecadd
1 changed files with 7 additions and 2 deletions
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9
drivers/gpu/drm/drm_fb_helper.c
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@ -89,8 +89,9 @@ static LIST_HEAD(kernel_fb_helper_list);
* connectors to the fbdev, e.g. if some are reserved for special purposes or * connectors to the fbdev, e.g. if some are reserved for special purposes or
* not adequate to be used for the fbcon. * not adequate to be used for the fbcon.
* *
* Since this is part of the initial setup before the fbdev is published, no * This function is protected against concurrent connector hotadds/removals
* locking is required. * using drm_fb_helper_add_one_connector() and
* drm_fb_helper_remove_one_connector().
*/ */
int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper) int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
{ {
@ -98,6 +99,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
struct drm_connector *connector; struct drm_connector *connector;
int i; int i;
mutex_lock(&dev->mode_config.mutex);
drm_for_each_connector(connector, dev) { drm_for_each_connector(connector, dev) {
struct drm_fb_helper_connector *fb_helper_connector; struct drm_fb_helper_connector *fb_helper_connector;
@ -108,6 +110,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
fb_helper_connector->connector = connector; fb_helper_connector->connector = connector;
fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector; fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector;
} }
mutex_unlock(&dev->mode_config.mutex);
return 0; return 0;
fail: fail:
for (i = 0; i < fb_helper->connector_count; i++) { for (i = 0; i < fb_helper->connector_count; i++) {
@ -115,6 +118,8 @@ fail:
fb_helper->connector_info[i] = NULL; fb_helper->connector_info[i] = NULL;
} }
fb_helper->connector_count = 0; fb_helper->connector_count = 0;
mutex_unlock(&dev->mode_config.mutex);
return -ENOMEM; return -ENOMEM;
} }
EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors); EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors);