[PATCH 06/19] drm/i915/vrr: Use crtc_vtotal for vmin

[Nautiyal, Ankit K]

On 2/17/2025 11:38 PM, Ville Syrjälä wrote:
> On Fri, Feb 14, 2025 at 05:41:16PM +0530, Ankit Nautiyal wrote:
>> To have fixed refresh rate with VRR timing generator the
>> guardband/pipeline full can't be programmed on the fly. So we need to
>> ensure that the values satisfy both the fixed and variable refresh
>> rates.
>>
>> Since we compute these value based on vmin, lets set the vmin to
>> crtc_vtotal for both fixed and variable timings instead of using the
>> current refresh rate based approach. This way the guardband remains
>> sufficient for both cases.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_vrr.c | 34 +++++++++++++++++-------
>>   1 file changed, 25 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
>> index efa2aa284285..3bcf2a026ad3 100644
>> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
>> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
>> @@ -246,18 +246,34 @@ void intel_vrr_compute_vrr_timings(struct intel_crtc_state *crtc_state)
>>   	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
>>   }
>>   
>> +/*
>> + * For fixed refresh rate mode Vmin, Vmax and Flipline all are set to
>> + * Vtotal value.
>> + */
>>   static
>> -int intel_vrr_compute_vmin(struct intel_connector *connector,
>> -			   struct drm_display_mode *adjusted_mode)
>> +int intel_vrr_fixed_rr_vtotal(const struct intel_crtc_state *crtc_state)
>>   {
>> -	int vmin;
>> -	const struct drm_display_info *info = &connector->base.display_info;
>> +	struct intel_display *display = to_intel_display(crtc_state);
>> +	int crtc_vtotal = crtc_state->hw.adjusted_mode.crtc_vtotal;
>>   
>> -	vmin = DIV_ROUND_UP(adjusted_mode->crtc_clock * 1000,
>> -			    adjusted_mode->crtc_htotal * info->monitor_range.max_vfreq);
>> -	vmin = max_t(int, vmin, adjusted_mode->crtc_vtotal);
>> +	if (DISPLAY_VER(display) >= 13)
>> +		return crtc_vtotal;
>> +	else
>> +		return crtc_vtotal -
>> +			intel_vrr_real_vblank_delay(crtc_state);
>> +}
>>   
>> -	return vmin;
>> +static
>> +int intel_vrr_compute_vmin(struct intel_crtc_state *crtc_state)
>> +{
>> +	/*
>> +	 * To make fixed rr and vrr work seamless the guardband/pipeline full
>> +	 * should be set such that it satisfies both the fixed and variable
>> +	 * timings.
>> +	 * For this set the vmin as crtc_vtotal. With this we never need to
>> +	 * change anything to do with the guardband.
>> +	 */
>> +	return intel_vrr_fixed_rr_vtotal(crtc_state);
> We don't have the vblank delay dialed in at this point. So this
> needs to be just the normal vtotal wihtout any adjustments.

Indeed. Will make the changes without the adjustments.

Regards,

Ankit

>
>>   }
>>   
>>   static
>> @@ -305,7 +321,7 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
>>   	if (HAS_LRR(display))
>>   		crtc_state->update_lrr = true;
>>   
>> -	vmin = intel_vrr_compute_vmin(connector, adjusted_mode);
>> +	vmin = intel_vrr_compute_vmin(crtc_state);
>>   	vmax = intel_vrr_compute_vmax(connector, adjusted_mode);
>>   
>>   	if (vmin >= vmax)
>> -- 
>> 2.45.2