diff options
Diffstat (limited to 'drivers/gpu/drm/i915')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_pm.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index d55bf882d1aa..aece0ff88a5d 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -8354,22 +8354,24 @@ void intel_pm_setup(struct drm_i915_private *dev_priv) static u64 vlv_residency_raw(struct drm_i915_private *dev_priv, const i915_reg_t reg) { - u32 lower, upper, tmp, saved_ctl; + u32 lower, upper, tmp; /* The register accessed do not need forcewake. We borrow * uncore lock to prevent concurrent access to range reg. */ spin_lock_irq(&dev_priv->uncore.lock); - saved_ctl = I915_READ_FW(VLV_COUNTER_CONTROL); - - if (WARN_ON(!(saved_ctl & VLV_COUNT_RANGE_HIGH))) - I915_WRITE_FW(VLV_COUNTER_CONTROL, - _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH)); /* vlv and chv residency counters are 40 bits in width. * With a control bit, we can choose between upper or lower * 32bit window into this counter. + * + * Although we always use the counter in high-range mode elsewhere, + * userspace may attempt to read the value before rc6 is initialised, + * before we have set the default VLV_COUNTER_CONTROL value. So always + * set the high bit to be safe. */ + I915_WRITE_FW(VLV_COUNTER_CONTROL, + _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH)); upper = I915_READ_FW(reg); do { tmp = upper; @@ -8383,6 +8385,11 @@ static u64 vlv_residency_raw(struct drm_i915_private *dev_priv, upper = I915_READ_FW(reg); } while (upper != tmp); + /* Everywhere else we always use VLV_COUNTER_CONTROL with the + * VLV_COUNT_RANGE_HIGH bit set - so it is safe to leave it set + * now. + */ + spin_unlock_irq(&dev_priv->uncore.lock); return lower | (u64)upper << 8; |