Re: [PATCH] drm/i915: Handle changing enable_psr parameter at runtime better

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Op 07-03-18 om 23:22 schreef Pandiyan, Dhinakaran:
> On Wed, 2018-03-07 at 17:39 +0100, Maarten Lankhorst wrote:
>> Similar to enable_fbc, enable_psr was ignored at runtime if it was
>> changed. The easiest fix is to pretend enable_psr is ignored at
>> configure time, and never activate it for !enable_psr, so both cases
>> are handled without modesets.
> What about cases where psr_flush() is not called and consequently the
> module parameter is not checked? With HW tracking, PSR is
> enabled/disabled during modeset and the hardware is expected to exit and
> activate PSR without driver intervention.
It looks like intel_frontbuffer_flush always calls intel_psr_flush,
so we at least get a PSR toggle after every atomic commit?

~Maarten

>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> Tested-by: Benjamin Berg <bberg@redhat.com>
>> Cc: Benjamin Berg <bberg@redhat.com>
>> ---
>>  drivers/gpu/drm/i915/intel_psr.c | 19 ++++++++++---------
>>  1 file changed, 10 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
>> index 23175c5c4a50..ac3ce7a1c2a7 100644
>> --- a/drivers/gpu/drm/i915/intel_psr.c
>> +++ b/drivers/gpu/drm/i915/intel_psr.c
>> @@ -502,11 +502,6 @@ void intel_psr_compute_config(struct intel_dp *intel_dp,
>>  	if (!CAN_PSR(dev_priv))
>>  		return;
>>  
>> -	if (!i915_modparams.enable_psr) {
>> -		DRM_DEBUG_KMS("PSR disable by flag\n");
>> -		return;
>> -	}
>> -
>>  	/*
>>  	 * HSW spec explicitly says PSR is tied to port A.
>>  	 * BDW+ platforms with DDI implementation of PSR have different
>> @@ -559,7 +554,10 @@ void intel_psr_compute_config(struct intel_dp *intel_dp,
>>  
>>  	crtc_state->has_psr = true;
>>  	crtc_state->has_psr2 = intel_psr2_config_valid(intel_dp, crtc_state);
>> -	DRM_DEBUG_KMS("Enabling PSR%s\n", crtc_state->has_psr2 ? "2" : "");
>> +	if (i915_modparams.enable_psr)
>> +		DRM_DEBUG_KMS("Enabling PSR%s\n", crtc_state->has_psr2 ? "2" : "");
>> +	else
>> +		DRM_DEBUG_KMS("PSR disable by flag\n");
>>  }
>>  
>>  static void intel_psr_activate(struct intel_dp *intel_dp)
>> @@ -652,7 +650,9 @@ void intel_psr_enable(struct intel_dp *intel_dp,
>>  	dev_priv->psr.enable_source(intel_dp, crtc_state);
>>  	dev_priv->psr.enabled = intel_dp;
>>  
>> -	if (INTEL_GEN(dev_priv) >= 9) {
>> +	if (!i915_modparams.enable_psr) {
>> +		DRM_DEBUG_KMS("PSR disable by flag\n");
>> +	} else if (INTEL_GEN(dev_priv) >= 9) {
>>  		intel_psr_activate(intel_dp);
>>  	} else {
>>  		/*
>> @@ -843,7 +843,7 @@ static void intel_psr_work(struct work_struct *work)
>>  	 * recheck. Since psr_flush first clears this and then reschedules we
>>  	 * won't ever miss a flush when bailing out here.
>>  	 */
>> -	if (dev_priv->psr.busy_frontbuffer_bits)
>> +	if (dev_priv->psr.busy_frontbuffer_bits || !i915_modparams.enable_psr)
>>  		goto unlock;
>>  
>>  	intel_psr_activate(intel_dp);
>> @@ -1015,7 +1015,8 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
>>  		return;
>>  
>>  	mutex_lock(&dev_priv->psr.lock);
>> -	if (!dev_priv->psr.enabled) {
>> +	if (!dev_priv->psr.enabled || !i915_modparams.enable_psr) {
>> +		intel_psr_exit(dev_priv);
>>  		mutex_unlock(&dev_priv->psr.lock);
>>  		return;
>>  	}


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