From 169faecadd2444fc295c724c0a2f622b99e6bf19 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 9 Jul 2015 23:44:27 +0200 Subject: [PATCH] drm/fbdev-helper: Grab mode_config.mutex in drm_fb_helper_single_add_all_connectors 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 Signed-off-by: Daniel Vetter --- 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); -- 2.39.2