Vlv and chv residency counters are 40 bits in width. With a control bit, we can choose between upper or lower 32 bit window into this counter.
Lets toggle this bit on and off on and read both parts. As a result we can push the wrap from 13 seconds to 54 minutes. v2: commit msg, loop readability, goto elimination (Chris) v3: bug ref, divide outside runtime pm lock (Chris) References: https://bugs.freedesktop.org/show_bug.cgi?id=94852 Reported-by: Len Brown <[email protected]> Cc: Chris Wilson <[email protected]> Cc: Ville Syrjälä <[email protected]> Signed-off-by: Mika Kuoppala <[email protected]> Reviewed-by: Chris Wilson <[email protected]> --- drivers/gpu/drm/i915/intel_pm.c | 60 ++++++++++++++++++++++++++++++++++------- 1 file changed, 51 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index da742a9..dcf1b72 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -8350,12 +8350,51 @@ void intel_pm_setup(struct drm_i915_private *dev_priv) atomic_set(&dev_priv->pm.wakeref_count, 0); } +static u64 vlv_residency_raw(struct drm_i915_private *dev_priv, + const i915_reg_t reg) +{ + u32 lower, upper, tmp, saved_ctl; + + /* 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 (!(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. + */ + upper = I915_READ_FW(reg); + do { + tmp = upper; + + I915_WRITE_FW(VLV_COUNTER_CONTROL, + _MASKED_BIT_DISABLE(VLV_COUNT_RANGE_HIGH)); + lower = I915_READ_FW(reg); + + I915_WRITE_FW(VLV_COUNTER_CONTROL, + _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH)); + upper = I915_READ_FW(reg); + } while (upper != tmp); + + if (!(saved_ctl & VLV_COUNT_RANGE_HIGH)) + I915_WRITE_FW(VLV_COUNTER_CONTROL, + _MASKED_BIT_DISABLE(VLV_COUNT_RANGE_HIGH)); + + spin_unlock_irq(&dev_priv->uncore.lock); + + return lower | (u64)upper << 8; +} + u64 intel_rc6_residency_us(struct drm_i915_private *dev_priv, const i915_reg_t reg) { - u64 raw_time; /* 32b value may overflow during fixed point math */ - u64 units = 128000ULL, div = 100000ULL; - u64 ret; + u64 time_hw, units, div; if (!intel_enable_rc6()) return 0; @@ -8367,16 +8406,19 @@ u64 intel_rc6_residency_us(struct drm_i915_private *dev_priv, units = 1000; div = dev_priv->czclk_freq; - if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH) - units <<= 8; + time_hw = vlv_residency_raw(dev_priv, reg); } else if (IS_GEN9_LP(dev_priv)) { units = 1000; div = 1200; /* 833.33ns */ - } - raw_time = I915_READ(reg) * units; - ret = DIV_ROUND_UP_ULL(raw_time, div); + time_hw = I915_READ(reg); + } else { + units = 128000; /* 1.28us */ + div = 100000; + + time_hw = I915_READ(reg); + } intel_runtime_pm_put(dev_priv); - return ret; + return DIV_ROUND_UP_ULL(time_hw * units, div); } -- 2.7.4 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
