Re: [PATCH] drm/i915: Fix gpu frequency change tracing

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 17 Nov 2015, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> On Tue, Nov 17, 2015 at 06:14:26PM +0200, Mika Kuoppala wrote:
>> With gen < 9 we have had always 50Mhz units as our hw
>> ratio. With gen >= 9 the hw ratio changed to 16.667Mhz (50/3).
>> The result was that our gpu frequency tracing started to output
>> values 3 times larger than expected due to hardcoded scaling
>> value. Fix this by using  Use intel_gpu_freq() when generating Mhz
>> value from ratio for 'intel_gpu_freq_change' trace event.
>> 
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92591
>> Reported-by: Eero Tamminen <eero.t.tamminen@intel.com>
>> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_pm.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>> index ebd6735..656c53a 100644
>> --- a/drivers/gpu/drm/i915/intel_pm.c
>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>> @@ -4330,7 +4330,7 @@ static void gen6_set_rps(struct drm_device *dev, u8 val)
>>  	POSTING_READ(GEN6_RPNSWREQ);
>>  
>>  	dev_priv->rps.cur_freq = val;
>> -	trace_intel_gpu_freq_change(val * 50);
>> +	trace_intel_gpu_freq_change(intel_gpu_freq(dev_priv, val));
>
> I was thinking maybe moving it to the caller to avoid having it in both
> the gen6 and vlv set_rps functions, but there are actually so many callers
> that we're better off leaving it here.
>
> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Pushed to drm-intel-fixes with cc: stable for v4.3+, thanks for the
patch and review.

BR,
Jani.


>
>>  }
>>  
>>  static void valleyview_set_rps(struct drm_device *dev, u8 val)
>> -- 
>> 2.5.0
>> 
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-- 
Jani Nikula, Intel Open Source Technology Center
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