[Intel-gfx] [PATCH 2/4] drm/i915: protect backlight registers and data with a spinlock
Jani Nikula
jani.nikula at intel.com
Fri Apr 12 14:18:37 CEST 2013
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 <jani.nikula at intel.com>
---
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 3b315ba..7751660 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1629,6 +1629,7 @@ 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 b5a495a..9aa9d60 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -952,6 +952,7 @@ 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 41f0fde..88b9a66 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 acab67c..464c3d7 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)
@@ -432,13 +455,18 @@ 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);
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;
--
1.7.9.5
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