Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> writes:
> On Thu, Mar 02, 2017 at 08:01:40PM +0200, Mika Kuoppala wrote:
>> We were passively acting on the high counter value bit
>> and as it was never set, we were only utilizing the
>> the 32bits of resolution. As the divisor with these platforms
>> is quite high, the wrap around happened in the less than 13 seconds.
>>
>> If we toggle the resolution bit in the control register and
>
> Can't be done on all machines. IIRC both Chris and me tried this at
> some point and on some machines the register was locked. Also I'm
> not sure if some piece of firmware depends on the original setting.
>
With J1900 byt it seems to work.
-Mika
>> read twice we can get 8 bits more, bringing the wrap in
>> 54 minute range.
>>
>> Reported-by: Len Brown <len.brown@xxxxxxxxx>
>> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> Cc: Len Brown <len.brown@xxxxxxxxx>
>> Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/i915_sysfs.c | 15 ++++++++++++---
>> 1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
>> index af0ac9f..807d7be 100644
>> --- a/drivers/gpu/drm/i915/i915_sysfs.c
>> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
>> @@ -53,17 +53,26 @@ static u32 calc_residency(struct drm_i915_private *dev_priv,
>>
>> /* On VLV and CHV, residency time is in CZ units rather than 1.28us */
>> if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
>> - units = 1;
>> + u32 lower, upper;
>> div = dev_priv->czclk_freq;
>>
>> - if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
>> - units <<= 8;
>> + I915_WRITE(VLV_COUNTER_CONTROL,
>> + _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH));
>> + upper = I915_READ(reg);
>> +
>> + I915_WRITE(VLV_COUNTER_CONTROL,
>> + _MASKED_BIT_DISABLE(VLV_COUNT_RANGE_HIGH));
>> + lower = I915_READ(reg);
>> +
>> + raw_time = lower | (u64)upper << 8;
>> + goto out;
>> } else if (IS_GEN9_LP(dev_priv)) {
>> units = 1;
>> div = 1200; /* 833.33ns */
>> }
>>
>> raw_time = I915_READ(reg) * units;
>> + out:
>> ret = DIV_ROUND_UP_ULL(raw_time, div);
>>
>> intel_runtime_pm_put(dev_priv);
>> --
>> 2.7.4
>
> --
> Ville Syrjälä
> Intel OTC
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