drm/i915: Avoid race of intel_crt_detect_hotplug() with HPD interrupt, v2
An HPD interrupt may fire while we are in a function that changes the PORT_HOTPLUG_EN register - especially when an HPD interrupt storm occurs. Since the interrupt handler changes the enabled HPD lines when it detects such a storm the read-modify-write cycles may interfere. To avoid this, shiled the rmw cycles with IRQ save spinlocks. Changes since v1: - Implement a function which takes care of accessing PORT_HOTPLUG_EN. Signed-off-by: Egbert Eich <eich@suse.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Egbert Eich
Daniel Vetter
Родитель
8204502a6a
Коммит
0706f17c30
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@ -2742,6 +2742,9 @@ i915_disable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,
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void valleyview_enable_display_irqs(struct drm_i915_private *dev_priv);
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void valleyview_disable_display_irqs(struct drm_i915_private *dev_priv);
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void i915_hotplug_interrupt_update(struct drm_i915_private *dev_priv,
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uint32_t mask,
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uint32_t bits);
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void
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ironlake_enable_display_irq(struct drm_i915_private *dev_priv, u32 mask);
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void
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@ -167,6 +167,44 @@ static const u32 hpd_bxt[HPD_NUM_PINS] = {
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static void gen6_rps_irq_handler(struct drm_i915_private *dev_priv, u32 pm_iir);
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/* For display hotplug interrupt */
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static inline void
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i915_hotplug_interrupt_update_locked(struct drm_i915_private *dev_priv,
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uint32_t mask,
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uint32_t bits)
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{
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uint32_t val;
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assert_spin_locked(&dev_priv->irq_lock);
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WARN_ON(bits & ~mask);
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val = I915_READ(PORT_HOTPLUG_EN);
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val &= ~mask;
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val |= bits;
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I915_WRITE(PORT_HOTPLUG_EN, val);
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}
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/**
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* i915_hotplug_interrupt_update - update hotplug interrupt enable
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* @dev_priv: driver private
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* @mask: bits to update
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* @bits: bits to enable
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* NOTE: the HPD enable bits are modified both inside and outside
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* of an interrupt context. To avoid that read-modify-write cycles
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* interfer, these bits are protected by a spinlock. Since this
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* function is usually not called from a context where the lock is
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* held already, this function acquires the lock itself. A non-locking
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* version is also available.
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*/
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void i915_hotplug_interrupt_update(struct drm_i915_private *dev_priv,
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uint32_t mask,
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uint32_t bits)
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{
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spin_lock_irq(&dev_priv->irq_lock);
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i915_hotplug_interrupt_update_locked(dev_priv, mask, bits);
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spin_unlock_irq(&dev_priv->irq_lock);
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}
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/**
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* ilk_update_display_irq - update DEIMR
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* @dev_priv: driver private
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@ -3050,7 +3088,7 @@ static void vlv_display_irq_reset(struct drm_i915_private *dev_priv)
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{
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enum pipe pipe;
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xFFFFFFFF, 0);
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I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
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for_each_pipe(dev_priv, pipe)
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@ -3466,7 +3504,7 @@ static void vlv_display_irq_postinstall(struct drm_i915_private *dev_priv)
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{
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dev_priv->irq_mask = ~0;
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xffffffff, 0);
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POSTING_READ(PORT_HOTPLUG_EN);
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I915_WRITE(VLV_IIR, 0xffffffff);
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@ -3840,7 +3878,7 @@ static void i915_irq_preinstall(struct drm_device * dev)
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int pipe;
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if (I915_HAS_HOTPLUG(dev)) {
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xffffffff, 0);
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I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
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}
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@ -3874,7 +3912,7 @@ static int i915_irq_postinstall(struct drm_device *dev)
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I915_USER_INTERRUPT;
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if (I915_HAS_HOTPLUG(dev)) {
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xffffffff, 0);
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POSTING_READ(PORT_HOTPLUG_EN);
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/* Enable in IER... */
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@ -4036,7 +4074,7 @@ static void i915_irq_uninstall(struct drm_device * dev)
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int pipe;
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if (I915_HAS_HOTPLUG(dev)) {
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xffffffff, 0);
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I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
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}
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@ -4057,7 +4095,7 @@ static void i965_irq_preinstall(struct drm_device * dev)
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struct drm_i915_private *dev_priv = dev->dev_private;
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int pipe;
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xffffffff, 0);
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I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
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I915_WRITE(HWSTAM, 0xeffe);
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@ -4118,7 +4156,7 @@ static int i965_irq_postinstall(struct drm_device *dev)
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I915_WRITE(IER, enable_mask);
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POSTING_READ(IER);
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xffffffff, 0);
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POSTING_READ(PORT_HOTPLUG_EN);
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i915_enable_asle_pipestat(dev);
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@ -4133,22 +4171,22 @@ static void i915_hpd_irq_setup(struct drm_device *dev)
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assert_spin_locked(&dev_priv->irq_lock);
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hotplug_en = I915_READ(PORT_HOTPLUG_EN);
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hotplug_en &= ~HOTPLUG_INT_EN_MASK;
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/* Note HDMI and DP share hotplug bits */
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/* enable bits are the same for all generations */
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hotplug_en |= intel_hpd_enabled_irqs(dev, hpd_mask_i915);
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hotplug_en = intel_hpd_enabled_irqs(dev, hpd_mask_i915);
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/* Programming the CRT detection parameters tends
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to generate a spurious hotplug event about three
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seconds later. So just do it once.
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*/
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if (IS_G4X(dev))
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hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
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hotplug_en &= ~CRT_HOTPLUG_VOLTAGE_COMPARE_MASK;
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hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
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/* Ignore TV since it's buggy */
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I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
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i915_hotplug_interrupt_update_locked(dev_priv,
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(HOTPLUG_INT_EN_MASK
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| CRT_HOTPLUG_VOLTAGE_COMPARE_MASK),
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hotplug_en);
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}
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static irqreturn_t i965_irq_handler(int irq, void *arg)
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@ -4261,7 +4299,7 @@ static void i965_irq_uninstall(struct drm_device * dev)
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if (!dev_priv)
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return;
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I915_WRITE(PORT_HOTPLUG_EN, 0);
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i915_hotplug_interrupt_update(dev_priv, 0xffffffff, 0);
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I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
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I915_WRITE(HWSTAM, 0xffffffff);
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@ -376,7 +376,7 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector)
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{
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struct drm_device *dev = connector->dev;
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struct drm_i915_private *dev_priv = dev->dev_private;
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u32 hotplug_en, orig, stat;
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u32 stat;
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bool ret = false;
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int i, tries = 0;
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@ -395,12 +395,12 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector)
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tries = 2;
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else
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tries = 1;
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hotplug_en = orig = I915_READ(PORT_HOTPLUG_EN);
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hotplug_en |= CRT_HOTPLUG_FORCE_DETECT;
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for (i = 0; i < tries ; i++) {
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/* turn on the FORCE_DETECT */
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I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
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i915_hotplug_interrupt_update(dev_priv,
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CRT_HOTPLUG_FORCE_DETECT,
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CRT_HOTPLUG_FORCE_DETECT);
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/* wait for FORCE_DETECT to go off */
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if (wait_for((I915_READ(PORT_HOTPLUG_EN) &
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CRT_HOTPLUG_FORCE_DETECT) == 0,
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@ -415,8 +415,7 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector)
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/* clear the interrupt we just generated, if any */
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I915_WRITE(PORT_HOTPLUG_STAT, CRT_HOTPLUG_INT_STATUS);
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/* and put the bits back */
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I915_WRITE(PORT_HOTPLUG_EN, orig);
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i915_hotplug_interrupt_update(dev_priv, CRT_HOTPLUG_FORCE_DETECT, 0);
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return ret;
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}
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