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drm/i915: Use a global lock for modifying global irq flags
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We were attempting to use a per-ring spinlock whilst modifying global
IRQ flags. A recipe for rare missed interrupts.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Chris Wilson authored and Daniel Vetter committed May 3, 2012
1 parent 97e1930 commit 7338aef
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Showing 2 changed files with 25 additions and 19 deletions.
41 changes: 24 additions & 17 deletions drivers/gpu/drm/i915/intel_ringbuffer.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -610,17 +610,18 @@ gen5_ring_get_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

if (!dev->irq_enabled)
return false;

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (ring->irq_refcount++ == 0) {
dev_priv->gt_irq_mask &= ~ring->irq_enable_mask;
I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
POSTING_READ(GTIMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

return true;
}
Expand All @@ -630,32 +631,34 @@ gen5_ring_put_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (--ring->irq_refcount == 0) {
dev_priv->gt_irq_mask |= ring->irq_enable_mask;
I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
POSTING_READ(GTIMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
}

static bool
i9xx_ring_get_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

if (!dev->irq_enabled)
return false;

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (ring->irq_refcount++ == 0) {
dev_priv->irq_mask &= ~ring->irq_enable_mask;
I915_WRITE(IMR, dev_priv->irq_mask);
POSTING_READ(IMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

return true;
}
Expand All @@ -665,32 +668,34 @@ i9xx_ring_put_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (--ring->irq_refcount == 0) {
dev_priv->irq_mask |= ring->irq_enable_mask;
I915_WRITE(IMR, dev_priv->irq_mask);
POSTING_READ(IMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
}

static bool
i8xx_ring_get_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

if (!dev->irq_enabled)
return false;

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (ring->irq_refcount++ == 0) {
dev_priv->irq_mask &= ~ring->irq_enable_mask;
I915_WRITE16(IMR, dev_priv->irq_mask);
POSTING_READ16(IMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

return true;
}
Expand All @@ -700,14 +705,15 @@ i8xx_ring_put_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (--ring->irq_refcount == 0) {
dev_priv->irq_mask |= ring->irq_enable_mask;
I915_WRITE16(IMR, dev_priv->irq_mask);
POSTING_READ16(IMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
}

void intel_ring_setup_status_page(struct intel_ring_buffer *ring)
Expand Down Expand Up @@ -786,6 +792,7 @@ gen6_ring_get_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

if (!dev->irq_enabled)
return false;
Expand All @@ -795,14 +802,14 @@ gen6_ring_get_irq(struct intel_ring_buffer *ring)
* blt/bsd rings on ivb. */
gen6_gt_force_wake_get(dev_priv);

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (ring->irq_refcount++ == 0) {
I915_WRITE_IMR(ring, ~ring->irq_enable_mask);
dev_priv->gt_irq_mask &= ~ring->irq_enable_mask;
I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
POSTING_READ(GTIMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

return true;
}
Expand All @@ -812,15 +819,16 @@ gen6_ring_put_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long flags;

spin_lock(&ring->irq_lock);
spin_lock_irqsave(&dev_priv->irq_lock, flags);
if (--ring->irq_refcount == 0) {
I915_WRITE_IMR(ring, ~0);
dev_priv->gt_irq_mask |= ring->irq_enable_mask;
I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
POSTING_READ(GTIMR);
}
spin_unlock(&ring->irq_lock);
spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

gen6_gt_force_wake_put(dev_priv);
}
Expand Down Expand Up @@ -954,7 +962,6 @@ static int intel_init_ring_buffer(struct drm_device *dev,
ring->size = 32 * PAGE_SIZE;

init_waitqueue_head(&ring->irq_queue);
spin_lock_init(&ring->irq_lock);

if (I915_NEED_GFX_HWS(dev)) {
ret = init_status_page(ring);
Expand Down
3 changes: 1 addition & 2 deletions drivers/gpu/drm/i915/intel_ringbuffer.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,8 +56,7 @@ struct intel_ring_buffer {
*/
u32 last_retired_head;

spinlock_t irq_lock;
u32 irq_refcount;
u32 irq_refcount; /* protected by dev_priv->irq_lock */
u32 irq_enable_mask; /* bitmask to enable ring interrupt */
u32 irq_seqno; /* last seq seem at irq time */
u32 trace_irq_seqno;
Expand Down

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