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drm/i915: Terminate the FORCE WAKE after we have finished reading

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Once we have read the value out of the GT power well, we need to remove
the FORCE WAKE bit to allow the system to auto-power down.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Chris Wilson 2010-12-08 17:32:24 +00:00
parent a8e93126a6
commit eb43f4af7e
3 changed files with 35 additions and 9 deletions
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22
drivers/gpu/drm/i915/i915_drv.c
View file

@ -244,6 +244,28 @@ void intel_detect_pch (struct drm_device *dev)
}
}
void __gen6_force_wake_get(struct drm_i915_private *dev_priv)
{
int count;
count = 0;
while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_ACK) & 1))
udelay(10);
I915_WRITE_NOTRACE(FORCEWAKE, 1);
POSTING_READ(FORCEWAKE);
count = 0;
while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_ACK) & 1) == 0)
udelay(10);
}
void __gen6_force_wake_put(struct drm_i915_private *dev_priv)
{
I915_WRITE_NOTRACE(FORCEWAKE, 0);
POSTING_READ(FORCEWAKE);
}
static int i915_drm_freeze(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;

21
drivers/gpu/drm/i915/i915_drv.h
View file

@ -1341,17 +1341,20 @@ __i915_write(64, q)
* must be set to prevent GT core from power down and stale values being
* returned.
*/
void __gen6_force_wake_get(struct drm_i915_private *dev_priv);
void __gen6_force_wake_put (struct drm_i915_private *dev_priv);
static inline u32 i915_safe_read(struct drm_i915_private *dev_priv, u32 reg)
{
if (IS_GEN6(dev_priv->dev)) {
I915_WRITE_NOTRACE(FORCEWAKE, 1);
POSTING_READ(FORCEWAKE);
/* XXX How long do we really need to wait here?
* Will different registers/engines require different periods?
*/
udelay(100);
}
return I915_READ(reg);
u32 val;
if (dev_priv->info->gen >= 6) {
__gen6_force_wake_get(dev_priv);
val = I915_READ(reg);
__gen6_force_wake_put(dev_priv);
} else
val = I915_READ(reg);
return val;
}
static inline void

1
drivers/gpu/drm/i915/i915_reg.h
View file

@ -3115,4 +3115,5 @@
#define EDP_LINK_TRAIN_VOL_EMP_MASK_SNB (0x3f<<22)
#define FORCEWAKE 0xA18C
#define FORCEWAKE_ACK 0x130090
#endif /* _I915_REG_H_ */