[PATCH 8/8] drm: add drm_fb_helper_restore_fbdev_mode_unlocked()

Daniel Vetter daniel at ffwll.ch
Tue Jun 3 06:33:04 PDT 2014


On Fri, May 30, 2014 at 01:12:10PM -0400, Rob Clark wrote:
> All drm_fb_helper_restore_fbdev_mode() call sites, save one, do the same
> locking.  Simplify this into drm_fb_helper_restore_fbdev_mode_unlocked().
> 
> Signed-off-by: Rob Clark <robdclark at gmail.com>

Presuming I'm not blind the last such user is in the fb helper itself for
the panic handler. Should we drop the EXPORT_SYMBOL for the helper?

If we do that we might as well drop the _unlocked prefix and just remove
locking from drivers ...
-Daniel

> ---
>  drivers/gpu/drm/armada/armada_fbdev.c     |  4 +--
>  drivers/gpu/drm/drm_fb_cma_helper.c       |  9 ++----
>  drivers/gpu/drm/drm_fb_helper.c           | 51 +++++++++++++++++++++++--------
>  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               |  1 +
>  10 files changed, 50 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
> index 948cb14..fd166f5 100644
> --- a/drivers/gpu/drm/armada/armada_fbdev.c
> +++ b/drivers/gpu/drm/armada/armada_fbdev.c
> @@ -181,10 +181,8 @@ void armada_fbdev_lastclose(struct drm_device *dev)
>  {
>  	struct armada_private *priv = dev->dev_private;
>  
> -	drm_modeset_lock_all(dev);
>  	if (priv->fbdev)
> -		drm_fb_helper_restore_fbdev_mode(priv->fbdev);
> -	drm_modeset_unlock_all(dev);
> +		drm_fb_helper_restore_fbdev_mode_unlocked(priv->fbdev);
>  }
>  
>  void armada_fbdev_fini(struct drm_device *dev)
> diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
> index 61b5a47..f27c883 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_unlocked(&fbdev_cma->fb_helper);
>  }
>  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 b891f4c..dc861a1 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -273,15 +273,7 @@ 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)
> +static bool restore_fbdev_mode(struct drm_fb_helper *fb_helper)
>  {
>  	struct drm_device *dev = fb_helper->dev;
>  	struct drm_plane *plane;
> @@ -311,8 +303,44 @@ bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
>  	}
>  	return error;
>  }
> +/**
> + * 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.
> + *
> + * Use this variant if you need to bypass locking (panic), or already
> + * hold all modeset locks.  Otherwise use drm_fb_helper_restore_fbdev_mode_unlocked()
> + */
> +bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
> +{
> +	return restore_fbdev_mode(fb_helper);
> +}
>  EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode);
>  
> +/**
> + * drm_fb_helper_restore_fbdev_mode_unlocked - 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_unlocked(struct drm_fb_helper *fb_helper)
> +{
> +	struct drm_device *dev = fb_helper->dev;
> +	bool ret;
> +	drm_modeset_lock_all(dev);
> +	ret = restore_fbdev_mode(fb_helper);
> +	drm_modeset_unlock_all(dev);
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
> +
>  /*
>   * restore fbcon display for all kms driver's using this helper, used for sysrq
>   * and panic handling.
> @@ -824,7 +852,6 @@ EXPORT_SYMBOL(drm_fb_helper_check_var);
>  int drm_fb_helper_set_par(struct fb_info *info)
>  {
>  	struct drm_fb_helper *fb_helper = info->par;
> -	struct drm_device *dev = fb_helper->dev;
>  	struct fb_var_screeninfo *var = &info->var;
>  
>  	if (var->pixclock != 0) {
> @@ -832,9 +859,7 @@ int drm_fb_helper_set_par(struct fb_info *info)
>  		return -EINVAL;
>  	}
>  
> -	drm_modeset_lock_all(dev);
> -	drm_fb_helper_restore_fbdev_mode(fb_helper);
> -	drm_modeset_unlock_all(dev);
> +	drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
>  
>  	if (fb_helper->delayed_hotplug) {
>  		fb_helper->delayed_hotplug = false;
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> index addbf75..93e7ba6 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> @@ -375,7 +375,5 @@ 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_unlocked(private->fb_helper);
>  }
> diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c
> index 0a3101a..59ea45e 100644
> --- a/drivers/gpu/drm/gma500/psb_drv.c
> +++ b/drivers/gpu/drm/gma500/psb_drv.c
> @@ -112,11 +112,9 @@ static void psb_driver_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_unlocked(&fbdev->psb_fb_helper);
>  	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 fce4a0d..f8258ab 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -683,11 +683,7 @@ void intel_fbdev_restore_mode(struct drm_device *dev)
>  	if (!dev_priv->fbdev)
>  		return;
>  
> -	drm_modeset_lock_all(dev);
> -
> -	ret = drm_fb_helper_restore_fbdev_mode(&dev_priv->fbdev->helper);
> +	ret = drm_fb_helper_restore_fbdev_mode_unlocked(&dev_priv->fbdev->helper);
>  	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 50ec1be..afedd8b 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -382,11 +382,8 @@ 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_unlocked(priv->fbdev);
>  }
>  
>  static irqreturn_t msm_irq(int irq, void *arg)
> diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
> index c8270e4..002b972 100644
> --- a/drivers/gpu/drm/omapdrm/omap_drv.c
> +++ b/drivers/gpu/drm/omapdrm/omap_drv.c
> @@ -588,9 +588,7 @@ 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_unlocked(priv->fbdev);
>  	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 f7fca09..9798a70 100644
> --- a/drivers/gpu/drm/tegra/fb.c
> +++ b/drivers/gpu/drm/tegra/fb.c
> @@ -346,11 +346,8 @@ static void tegra_fbdev_free(struct tegra_fbdev *fbdev)
>  
>  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_unlocked(&fbdev->base);
>  }
>  
>  static void tegra_fb_output_poll_changed(struct drm_device *drm)
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index 6e622f7..0630b51 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -109,6 +109,7 @@ 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_unlocked(struct drm_fb_helper *fb_helper);
>  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,
> -- 
> 1.9.3
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch


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