From: Thierry Reding <treding@xxxxxxxxxx>
Introduce a new top-level lock for the FB helper code. This will allow
better locking granularity and avoid the need to abuse modeset locking
for this purpose instead.
Tested-by: John Stultz <john.stultz@xxxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 26 +++++++++++++++++++++++++-
include/drm/drm_fb_helper.h | 12 ++++++++++++
2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 18105cbe9810..860be51d92f6 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -119,6 +119,7 @@ static int __drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper,
if (!drm_fbdev_emulation)
return 0;
+ WARN_ON(!mutex_is_locked(&fb_helper->lock));
WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));
count = fb_helper->connector_count + 1;
@@ -150,11 +151,13 @@ int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper,
{
int err;
+ mutex_lock(&fb_helper->lock);
mutex_lock(&fb_helper->dev->mode_config.mutex);
err = __drm_fb_helper_add_one_connector(fb_helper, connector);
mutex_unlock(&fb_helper->dev->mode_config.mutex);
+ mutex_unlock(&fb_helper->lock);
return err;
}
@@ -184,6 +187,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
if (!drm_fbdev_emulation)
return 0;
+ mutex_lock(&fb_helper->lock);
mutex_lock(&dev->mode_config.mutex);
drm_connector_list_iter_begin(dev, &conn_iter);
drm_for_each_connector_iter(connector, &conn_iter) {
@@ -207,6 +211,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
out:
drm_connector_list_iter_end(&conn_iter);
mutex_unlock(&dev->mode_config.mutex);
+ mutex_unlock(&fb_helper->lock);
return ret;
}
@@ -221,6 +226,7 @@ static int __drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
if (!drm_fbdev_emulation)
return 0;
+ WARN_ON(!mutex_is_locked(&fb_helper->lock));
WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));
for (i = 0; i < fb_helper->connector_count; i++) {
@@ -247,11 +253,13 @@ int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
{
int err;
+ mutex_lock(&fb_helper->lock);
mutex_lock(&fb_helper->dev->mode_config.mutex);
err = __drm_fb_helper_remove_one_connector(fb_helper, connector);
mutex_unlock(&fb_helper->dev->mode_config.mutex);
+ mutex_unlock(&fb_helper->lock);
return err;
}
@@ -503,16 +511,21 @@ int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
if (!drm_fbdev_emulation)
return -ENODEV;
+ mutex_lock(&fb_helper->lock);
drm_modeset_lock_all(dev);
+
ret = restore_fbdev_mode(fb_helper);
do_delayed = fb_helper->delayed_hotplug;
if (do_delayed)
fb_helper->delayed_hotplug = false;
+
drm_modeset_unlock_all(dev);
+ mutex_unlock(&fb_helper->lock);
if (do_delayed)
drm_fb_helper_hotplug_event(fb_helper);
+
return ret;
}
EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
@@ -748,6 +761,7 @@ void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
INIT_WORK(&helper->resume_work, drm_fb_helper_resume_worker);
INIT_WORK(&helper->dirty_work, drm_fb_helper_dirty_work);
helper->dirty_clip.x1 = helper->dirty_clip.y1 = ~0;
+ mutex_init(&helper->lock);
helper->funcs = funcs;
helper->dev = dev;
}
@@ -913,6 +927,7 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
}
mutex_unlock(&kernel_fb_helper_lock);
+ mutex_destroy(&fb_helper->lock);
drm_fb_helper_crtc_free(fb_helper);
}
@@ -2422,25 +2437,34 @@ EXPORT_SYMBOL(drm_fb_helper_initial_config);
int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
{
struct drm_device *dev = fb_helper->dev;
+ int err = 0;
if (!drm_fbdev_emulation)
return 0;
+ mutex_lock(&fb_helper->lock);
mutex_lock(&dev->mode_config.mutex);
+
if (!fb_helper->fb || !drm_fb_helper_is_bound(fb_helper)) {
fb_helper->delayed_hotplug = true;
mutex_unlock(&dev->mode_config.mutex);
- return 0;
+ goto unlock;
}
+
DRM_DEBUG_KMS("\n");
drm_setup_crtcs(fb_helper, fb_helper->fb->width, fb_helper->fb->height);
mutex_unlock(&dev->mode_config.mutex);
+ mutex_unlock(&fb_helper->lock);
drm_fb_helper_set_par(fb_helper->fbdev);
return 0;
+
+unlock:
+ mutex_unlock(&fb_helper->lock);
+ return err;
}
EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 119e5e4609c7..44e2c57a7049 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -201,6 +201,18 @@ struct drm_fb_helper {
struct work_struct resume_work;
/**
+ * @lock:
+ *
+ * Top-level FB helper lock. This protects all internal data structures
+ * and lists, such as @connector_info and @crtc_info.
+ *
+ * FIXME: fbdev emulation locking is a mess and long term we want to
+ * protect all helper internal state with this lock as well as reduce
+ * core KMS locking as much as possible.
+ */
+ struct mutex lock;
+
+ /**
* @kernel_fb_list:
*
* Entry on the global kernel_fb_helper_list, used for kgdb entry/exit.
--
2.12.0
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