Re: [PATCH 13/17] drm: push locking down into restore_fbdev_mode

On Sat, May 24, 2014 at 02:30:22PM -0400, Rob Clark wrote:

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.

Signed-off-by: Rob Clark robdclark@gmail.com

Yeah, makes sense. But I don't like the bool lockless interface, especially since the only user of it is also in the fb helper.

Imo much better to add a static function with __ prefix internal to drm_fb_helper.c which is lockless and give drivers less rope to hang themselves. Since I just can't think of a good reason why they want to not have locking when force-restoring the fbdev emulation.

With that changed this is Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch

---

drivers/gpu/drm/armada/armada_fbdev.c | 4 +--- drivers/gpu/drm/drm_fb_cma_helper.c | 9 ++------- drivers/gpu/drm/drm_fb_helper.c | 17 ++++++++--------- 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 ++- 10 files changed, 21 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c index 948cb14..9976125 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(priv->fbdev, false);
  

}

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 65540b7..ccb7a9ac 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 4669e69..3815e1a 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) struct drm_atomic_state *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;

@@ -355,7 +357,7 @@ static bool drm_fb_helper_force_kernel_mode(void) continue; }

• ret = drm_fb_helper_restore_fbdev_mode(helper);
  

• ret = drm_fb_helper_restore_fbdev_mode(helper, true);
  

  if (ret) error = true;

@@ -840,7 +842,6 @@ 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) {

@@ -848,9 +849,7 @@ 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(fb_helper, false);

  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 2371716..486b21f 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(private->fb_helper, false);

} diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c index 0180292..72a35e3 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(&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 fce4a0d..28afd69 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(&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 46e0f29..d24ca45 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(priv->fbdev, false);
  

}

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 3f64c47..ad082f4 100644 --- a/drivers/gpu/drm/omapdrm/omap_drv.c +++ b/drivers/gpu/drm/omapdrm/omap_drv.c @@ -590,9 +590,7 @@ 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 f7fca09..85aae37 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(&fbdev->base, false);
  

}

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..99598a0 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, -- 1.9.0