[RFCv4 11/14] drm: push locking down into restore_fbdev_mode

[Rob Clark <robdclark@gmail.com>]

All the call-sites save one need locking.  By pushing it down and adding
a lockless flag, we can use the new spiffy atomic ww_mutex crtc locking
and simplify all the call-sites.
---
 drivers/gpu/drm/drm_fb_cma_helper.c       |  9 ++-------
 drivers/gpu/drm/drm_fb_helper.c           | 12 +++++++-----
 drivers/gpu/drm/exynos/exynos_drm_fbdev.c |  4 +---
 drivers/gpu/drm/gma500/psb_drv.c          |  4 +---
 drivers/gpu/drm/i915/intel_fbdev.c        |  6 +-----
 drivers/gpu/drm/msm/msm_drv.c             |  7 ++-----
 drivers/gpu/drm/omapdrm/omap_drv.c        |  4 +---
 drivers/gpu/drm/tegra/fb.c                |  7 ++-----
 include/drm/drm_fb_helper.h               |  3 ++-
 9 files changed, 19 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
index 61b5a47..df3ad41 100644
--- a/drivers/gpu/drm/drm_fb_cma_helper.c
+++ b/drivers/gpu/drm/drm_fb_cma_helper.c
@@ -429,13 +429,8 @@ EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);
  */
 void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma)
 {
-	if (fbdev_cma) {
-		struct drm_device *dev = fbdev_cma->fb_helper.dev;
-
-		drm_modeset_lock_all(dev);
-		drm_fb_helper_restore_fbdev_mode(&fbdev_cma->fb_helper);
-		drm_modeset_unlock_all(dev);
-	}
+	if (fbdev_cma)
+		drm_fb_helper_restore_fbdev_mode(&fbdev_cma->fb_helper, false);
 }
 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 5773468..294fe5e 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -276,12 +276,15 @@ EXPORT_SYMBOL(drm_fb_helper_debug_leave);
 /**
  * drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
  * @fb_helper: fbcon to restore
+ * @lockless: true in drm_fb_helper_force_kernel_mode() path, to avoid
+ *   blocking in panic case, everywhere else should use false
  *
  * 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 drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper,
+		bool lockless)
 {
 	struct drm_device *dev = fb_helper->dev;
 	struct drm_plane *plane;
@@ -289,9 +292,8 @@ bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
 	void *state;
 	int i;
 
-	drm_warn_on_modeset_not_all_locked(dev);
-
-	state = dev->driver->atomic_begin(dev, 0);
+	state = dev->driver->atomic_begin(dev, lockless ?
+			DRM_MODE_ATOMIC_NOLOCK : 0);
 	if (IS_ERR(state)) {
 		DRM_ERROR("failed to restore fbdev mode\n");
 		return true;
@@ -343,7 +345,7 @@ static bool drm_fb_helper_force_kernel_mode(void)
 		if (helper->dev->switch_power_state == DRM_SWITCH_POWER_OFF)
 			continue;
 
-		ret = drm_fb_helper_restore_fbdev_mode(helper);
+		ret = drm_fb_helper_restore_fbdev_mode(helper, true);
 		if (ret)
 			error = true;
 	}
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index e7c2f2d..8032021 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -354,7 +354,5 @@ 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);
+	drm_fb_helper_restore_fbdev_mode(private->fb_helper, false);
 }
diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c
index 34c3116..a6545fe 100644
--- a/drivers/gpu/drm/gma500/psb_drv.c
+++ b/drivers/gpu/drm/gma500/psb_drv.c
@@ -153,11 +153,9 @@ static void psb_lastclose(struct drm_device *dev)
 	struct drm_psb_private *dev_priv = dev->dev_private;
 	struct psb_fbdev *fbdev = dev_priv->fbdev;
 
-	drm_modeset_lock_all(dev);
-	ret = drm_fb_helper_restore_fbdev_mode(&fbdev->psb_fb_helper);
+	ret = drm_fb_helper_restore_fbdev_mode(&fbdev->psb_fb_helper, false);
 	if (ret)
 		DRM_DEBUG("failed to restore crtc mode\n");
-	drm_modeset_unlock_all(dev);
 
 	return;
 }
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index 895fcb4..4f7046d 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -313,11 +313,7 @@ void intel_fbdev_restore_mode(struct drm_device *dev)
 	if (INTEL_INFO(dev)->num_pipes == 0)
 		return;
 
-	drm_modeset_lock_all(dev);
-
-	ret = drm_fb_helper_restore_fbdev_mode(&dev_priv->fbdev->helper);
+	ret = drm_fb_helper_restore_fbdev_mode(&dev_priv->fbdev->helper, false);
 	if (ret)
 		DRM_DEBUG("failed to restore crtc mode\n");
-
-	drm_modeset_unlock_all(dev);
 }
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index dadd55a..cd7cd43 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -319,11 +319,8 @@ static void msm_preclose(struct drm_device *dev, struct drm_file *file)
 static void msm_lastclose(struct drm_device *dev)
 {
 	struct msm_drm_private *priv = dev->dev_private;
-	if (priv->fbdev) {
-		drm_modeset_lock_all(dev);
-		drm_fb_helper_restore_fbdev_mode(priv->fbdev);
-		drm_modeset_unlock_all(dev);
-	}
+	if (priv->fbdev)
+		drm_fb_helper_restore_fbdev_mode(priv->fbdev, false);
 }
 
 static irqreturn_t msm_irq(DRM_IRQ_ARGS)
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index 7a6c44a..cfd40f9 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -564,9 +564,7 @@ static void dev_lastclose(struct drm_device *dev)
 		}
 	}
 
-	drm_modeset_lock_all(dev);
-	ret = drm_fb_helper_restore_fbdev_mode(priv->fbdev);
-	drm_modeset_unlock_all(dev);
+	ret = drm_fb_helper_restore_fbdev_mode(priv->fbdev, false);
 	if (ret)
 		DBG("failed to restore crtc mode");
 }
diff --git a/drivers/gpu/drm/tegra/fb.c b/drivers/gpu/drm/tegra/fb.c
index 490f771..59f7fd1 100644
--- a/drivers/gpu/drm/tegra/fb.c
+++ b/drivers/gpu/drm/tegra/fb.c
@@ -384,9 +384,6 @@ void tegra_drm_fb_exit(struct drm_device *drm)
 
 void tegra_fbdev_restore_mode(struct tegra_fbdev *fbdev)
 {
-	if (fbdev) {
-		drm_modeset_lock_all(fbdev->base.dev);
-		drm_fb_helper_restore_fbdev_mode(&fbdev->base);
-		drm_modeset_unlock_all(fbdev->base.dev);
-	}
+	if (fbdev)
+		drm_fb_helper_restore_fbdev_mode(&fbdev->base, false);
 }
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 471f276..b130a4d 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -108,7 +108,8 @@ int drm_fb_helper_set_par(struct fb_info *info);
 int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 			    struct fb_info *info);
 
-bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper);
+bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper,
+		bool lockless);
 void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper,
 			    uint32_t fb_width, uint32_t fb_height);
 void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
-- 
1.8.4.2