From 6aed8ec3f76a22217c9ae183d32b1aa990bed069 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Sun, 20 Jan 2013 17:32:21 +0100 Subject: [PATCH] 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 Signed-off-by: Daniel Vetter --- 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 9c797f6fea75..f17077307c65 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 3742bc96421e..1b6ba2d4d60c 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 0c6e25e979dd..77378a1e907e 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 90d335cfb8c0..086d0f79785f 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 e90c8dcc028d..8b7762728639 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, -- 2.30.2