From 6aed8ec3f76a22217c9ae183d32b1aa990bed069 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Sun, 20 Jan 2013 17:32:21 +0100
Subject: drm: review locking for drm_fb_helper_restore_fbdev_mode
... it's required. Fix up exynos and the cma helper, and add a
corresponding WARN_ON to drm_fb_helper_restore_fbdev_mode.
Note that tegra calls the fbdev cma helper restore function also from
it's driver-load callback. Which is a bit against current practice,
since usually the call is only from ->lastclose, and initial setup is
done by drm_fb_helper_initial_config.
Also add the relevant drm DocBook entry.
v2: Add promised WARN to restore_fbdev_mode.
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/drm_crtc.c | 16 +++++++++++++++-
drivers/gpu/drm/drm_fb_cma_helper.c | 2 ++
drivers/gpu/drm/drm_fb_helper.c | 11 +++++++++++
drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 2 ++
include/drm/drm_crtc.h | 1 +
5 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 9c797f6fea7..f17077307c6 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -68,9 +68,23 @@ void drm_modeset_unlock_all(struct drm_device *dev)
mutex_unlock(&dev->mode_config.mutex);
}
-
EXPORT_SYMBOL(drm_modeset_unlock_all);
+/**
+ * drm_warn_on_modeset_not_all_locked - check that all modeset locks are locked
+ * @dev: device
+ */
+void drm_warn_on_modeset_not_all_locked(struct drm_device *dev)
+{
+ struct drm_crtc *crtc;
+
+ list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
+ WARN_ON(!mutex_is_locked(&crtc->mutex));
+
+ WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
+}
+EXPORT_SYMBOL(drm_warn_on_modeset_not_all_locked);
+
/* Avoid boilerplate. I'm tired of typing. */
#define DRM_ENUM_NAME_FN(fnname, list) \
char *fnname(int val) \
diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
index 3742bc96421..1b6ba2d4d60 100644
--- a/drivers/gpu/drm/drm_fb_cma_helper.c
+++ b/drivers/gpu/drm/drm_fb_cma_helper.c
@@ -389,8 +389,10 @@ EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);
*/
void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma)
{
+ drm_modeset_lock_all(dev);
if (fbdev_cma)
drm_fb_helper_restore_fbdev_mode(&fbdev_cma->fb_helper);
+ drm_modeset_unlock_all(dev);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_restore_mode);
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 0c6e25e979d..77378a1e907 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -239,10 +239,21 @@ int drm_fb_helper_debug_leave(struct fb_info *info)
}
EXPORT_SYMBOL(drm_fb_helper_debug_leave);
+/**
+ * drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
+ * @fb_helper: fbcon to restore
+ *
+ * This should be called from driver's drm->lastclose callback when implementing
+ * an fbcon on top of kms using this helper. This ensures that the user isn't
+ * greeted with a black screen when e.g. X dies.
+ */
bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
{
bool error = false;
int i, ret;
+
+ drm_warn_on_modeset_not_all_locked(fb_helper->dev);
+
for (i = 0; i < fb_helper->crtc_count; i++) {
struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
ret = drm_mode_set_config_internal(mode_set);
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index 90d335cfb8c..086d0f79785 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -376,5 +376,7 @@ void exynos_drm_fbdev_restore_mode(struct drm_device *dev)
if (!private || !private->fb_helper)
return;
+ drm_modeset_lock_all(dev);
drm_fb_helper_restore_fbdev_mode(private->fb_helper);
+ drm_modeset_unlock_all(dev);
}
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index e90c8dcc028..8b776272863 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -867,6 +867,7 @@ struct drm_prop_enum_list {
extern void drm_modeset_lock_all(struct drm_device *dev);
extern void drm_modeset_unlock_all(struct drm_device *dev);
+extern void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
extern int drm_crtc_init(struct drm_device *dev,
struct drm_crtc *crtc,
--
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