From 8ba2d18520ce380cf572e9902d9b3b91ece6c2c0 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Fri, 12 Apr 2013 15:18:37 +0300 Subject: [PATCH] drm/i915: protect backlight registers and data with a spinlock Backlight data and registers are fiddled through LVDS/eDP modeset enable/disable hooks, backlight sysfs files, asle interrupts, and register save/restore. Protect the backlight related registers and driver private fields using a spinlock. The locking in register save/restore covers a little more than is strictly necessary, including non-modeset case, for simplicity. v2: Cover register access, save/restore, i915_read_blc_pwm_ctl() and code paths leading there. Signed-off-by: Jani Nikula Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_dma.c | 1 + drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/i915_suspend.c | 10 ++++++++++ drivers/gpu/drm/i915/intel_panel.c | 30 ++++++++++++++++++++++++++++- 4 files changed, 41 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 13a72e63b4e9..a1648eb3a8b1 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -1633,6 +1633,7 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags) spin_lock_init(&dev_priv->irq_lock); spin_lock_init(&dev_priv->gpu_error.lock); spin_lock_init(&dev_priv->rps.lock); + spin_lock_init(&dev_priv->backlight.lock); mutex_init(&dev_priv->dpio_lock); mutex_init(&dev_priv->rps.hw_lock); diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 95a3cc367d50..f6f4839484d1 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -960,6 +960,7 @@ typedef struct drm_i915_private { struct { int level; bool enabled; + spinlock_t lock; /* bl registers and the above bl fields */ struct backlight_device *device; } backlight; diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c index 41f0fdecfbdc..88b9a663944f 100644 --- a/drivers/gpu/drm/i915/i915_suspend.c +++ b/drivers/gpu/drm/i915/i915_suspend.c @@ -192,6 +192,7 @@ static void i915_restore_vga(struct drm_device *dev) static void i915_save_display(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; + unsigned long flags; /* Display arbitration control */ if (INTEL_INFO(dev)->gen <= 4) @@ -202,6 +203,8 @@ static void i915_save_display(struct drm_device *dev) if (!drm_core_check_feature(dev, DRIVER_MODESET)) i915_save_display_reg(dev); + spin_lock_irqsave(&dev_priv->backlight.lock, flags); + /* LVDS state */ if (HAS_PCH_SPLIT(dev)) { dev_priv->regfile.savePP_CONTROL = I915_READ(PCH_PP_CONTROL); @@ -222,6 +225,8 @@ static void i915_save_display(struct drm_device *dev) dev_priv->regfile.saveLVDS = I915_READ(LVDS); } + spin_unlock_irqrestore(&dev_priv->backlight.lock, flags); + if (!IS_I830(dev) && !IS_845G(dev) && !HAS_PCH_SPLIT(dev)) dev_priv->regfile.savePFIT_CONTROL = I915_READ(PFIT_CONTROL); @@ -257,6 +262,7 @@ static void i915_restore_display(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; u32 mask = 0xffffffff; + unsigned long flags; /* Display arbitration */ if (INTEL_INFO(dev)->gen <= 4) @@ -265,6 +271,8 @@ static void i915_restore_display(struct drm_device *dev) if (!drm_core_check_feature(dev, DRIVER_MODESET)) i915_restore_display_reg(dev); + spin_lock_irqsave(&dev_priv->backlight.lock, flags); + /* LVDS state */ if (INTEL_INFO(dev)->gen >= 4 && !HAS_PCH_SPLIT(dev)) I915_WRITE(BLC_PWM_CTL2, dev_priv->regfile.saveBLC_PWM_CTL2); @@ -304,6 +312,8 @@ static void i915_restore_display(struct drm_device *dev) I915_WRITE(PP_CONTROL, dev_priv->regfile.savePP_CONTROL); } + spin_unlock_irqrestore(&dev_priv->backlight.lock, flags); + /* only restore FBC info on the platform that supports FBC*/ intel_disable_fbc(dev); if (I915_HAS_FBC(dev)) { diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 63a7c36a7603..5d3e9d7d51a7 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -138,6 +138,8 @@ static u32 i915_read_blc_pwm_ctl(struct drm_device *dev) struct drm_i915_private *dev_priv = dev->dev_private; u32 val; + WARN_ON(!spin_is_locked(&dev_priv->backlight.lock)); + /* Restore the CTL value if it lost, e.g. GPU reset */ if (HAS_PCH_SPLIT(dev_priv->dev)) { @@ -218,6 +220,9 @@ static u32 intel_panel_get_backlight(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; u32 val; + unsigned long flags; + + spin_lock_irqsave(&dev_priv->backlight.lock, flags); if (HAS_PCH_SPLIT(dev)) { val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK; @@ -235,6 +240,9 @@ static u32 intel_panel_get_backlight(struct drm_device *dev) } val = intel_panel_compute_brightness(dev, val); + + spin_unlock_irqrestore(&dev_priv->backlight.lock, flags); + DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val); return val; } @@ -282,11 +290,14 @@ void intel_panel_set_backlight(struct drm_device *dev, u32 level, u32 max) { struct drm_i915_private *dev_priv = dev->dev_private; u32 freq; + unsigned long flags; + + spin_lock_irqsave(&dev_priv->backlight.lock, flags); freq = intel_panel_get_max_backlight(dev); if (!freq) { /* we are screwed, bail out */ - return; + goto out; } /* scale to hardware */ @@ -298,11 +309,16 @@ void intel_panel_set_backlight(struct drm_device *dev, u32 level, u32 max) if (dev_priv->backlight.enabled) intel_panel_actually_set_backlight(dev, level); +out: + spin_unlock_irqrestore(&dev_priv->backlight.lock, flags); } void intel_panel_disable_backlight(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; + unsigned long flags; + + spin_lock_irqsave(&dev_priv->backlight.lock, flags); dev_priv->backlight.enabled = false; intel_panel_actually_set_backlight(dev, 0); @@ -320,12 +336,17 @@ void intel_panel_disable_backlight(struct drm_device *dev) I915_WRITE(BLC_PWM_PCH_CTL1, tmp); } } + + spin_unlock_irqrestore(&dev_priv->backlight.lock, flags); } void intel_panel_enable_backlight(struct drm_device *dev, enum pipe pipe) { struct drm_i915_private *dev_priv = dev->dev_private; + unsigned long flags; + + spin_lock_irqsave(&dev_priv->backlight.lock, flags); if (dev_priv->backlight.level == 0) { dev_priv->backlight.level = intel_panel_get_max_backlight(dev); @@ -375,6 +396,8 @@ set_level: */ dev_priv->backlight.enabled = true; intel_panel_actually_set_backlight(dev, dev_priv->backlight.level); + + spin_unlock_irqrestore(&dev_priv->backlight.lock, flags); } static void intel_panel_init_backlight(struct drm_device *dev) @@ -432,6 +455,7 @@ int intel_panel_setup_backlight(struct drm_connector *connector) struct drm_device *dev = connector->dev; struct drm_i915_private *dev_priv = dev->dev_private; struct backlight_properties props; + unsigned long flags; intel_panel_init_backlight(dev); @@ -441,7 +465,11 @@ int intel_panel_setup_backlight(struct drm_connector *connector) memset(&props, 0, sizeof(props)); props.type = BACKLIGHT_RAW; props.brightness = dev_priv->backlight.level; + + spin_lock_irqsave(&dev_priv->backlight.lock, flags); props.max_brightness = intel_panel_get_max_backlight(dev); + spin_unlock_irqrestore(&dev_priv->backlight.lock, flags); + if (props.max_brightness == 0) { DRM_DEBUG_DRIVER("Failed to get maximum backlight value\n"); return -ENODEV; -- 2.30.2