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.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 3630d92c9738..329d08167b77 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -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
* not adequate to be used for the fbcon.
*
- * Since this is part of the initial setup before the fbdev is published, no
- * locking is required.
+ * This function is protected against concurrent connector hotadds/removals
+ * 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)
{
@@ -98,6 +99,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
struct drm_connector *connector;
int i;
+ mutex_lock(&dev->mode_config.mutex);
drm_for_each_connector(connector, dev) {
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_info[fb_helper->connector_count++] = fb_helper_connector;
}
+ mutex_unlock(&dev->mode_config.mutex);
return 0;
fail:
for (i = 0; i < fb_helper->connector_count; i++) {
@@ -115,6 +118,8 @@ fail:
fb_helper->connector_info[i] = NULL;
}
fb_helper->connector_count = 0;
+ mutex_unlock(&dev->mode_config.mutex);
+
return -ENOMEM;
}
EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors);
--
2.1.4
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