[PATCH 16/19] drm/i915/display: Use fixed_rr timings in modeset sequence

Nautiyal, Ankit K ankit.k.nautiyal at intel.com
Wed Feb 19 13:57:00 UTC 2025


On 2/18/2025 12:26 AM, Ville Syrjälä wrote:
> On Mon, Feb 17, 2025 at 08:34:39PM +0200, Ville Syrjälä wrote:
>> On Fri, Feb 14, 2025 at 05:41:26PM +0530, Ankit Nautiyal wrote:
>>> During modeset enable sequence, program the fixed timings,
>>> and turn on the VRR Timing Generator (VRR TG) for platforms
>>> that always use VRR TG.
>>>
>>> Later if vrr timings are required, vrr_enable() will switch
>>> to the real VRR timings.
>>>
>>> With this we dont want to reset TRANS_CTL_VRR Enable bit while updating
>>> the vrr transcoder timings.
>>>
>>> v2: Update intel_vrr_set_transcoder_timings for fixed_rr.
>>> v3: Update intel_set_transcoder_timings_lrr for fixed_rr. (Ville)
>>>      Add TRANS_PUSH while enabling VRR for fixed_rr.
>>>
>>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/display/intel_display.c | 10 +++++--
>>>   drivers/gpu/drm/i915/display/intel_vrr.c     | 29 ++++++++++++++++++--
>>>   drivers/gpu/drm/i915/display/intel_vrr.h     |  3 ++
>>>   3 files changed, 36 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>>> index 66c5ad46bfea..c9d1c091b109 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>>> @@ -1755,6 +1755,7 @@ static void hsw_set_frame_start_delay(const struct intel_crtc_state *crtc_state)
>>>   
>>>   static void hsw_configure_cpu_transcoder(const struct intel_crtc_state *crtc_state)
>>>   {
>>> +	struct intel_display *display = to_intel_display(crtc_state);
>>>   	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>>>   	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>>>   	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>>> @@ -1770,9 +1771,12 @@ static void hsw_configure_cpu_transcoder(const struct intel_crtc_state *crtc_sta
>>>   	}
>>>   
>>>   	intel_set_transcoder_timings(crtc_state);
>>> -	if (HAS_VRR(dev_priv))
>>> -		intel_vrr_set_transcoder_timings(crtc_state);
>>> -
>>> +	if (HAS_VRR(dev_priv)) {
>>> +		if (intel_vrr_always_use_vrr_tg(display))
>>> +			intel_vrr_enable_fixed_rr_timings(crtc_state);
>>> +		else
>>> +			intel_vrr_set_transcoder_timings(crtc_state);
>> I think intel_vrr_set_transcoder_timings() should just program the
>> fixed timings always. And we shouldn't do anything else here.
>>
>> And I think the VRR_CTL enable/disable for the always_use_vrr_tg==true
>> case should be done at some more appropriate spot in the modeset
>> sequence. We can add eg. intel_vrr_trancoder_{enable,disable}() for
>> that part.
>>
>>> +	}
>>>   	if (cpu_transcoder != TRANSCODER_EDP)
>>>   		intel_de_write(dev_priv, TRANS_MULT(dev_priv, cpu_transcoder),
>>>   			       crtc_state->pixel_multiplier - 1);
>>> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
>>> index e247055bc486..4151fcd0f978 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
>>> @@ -456,8 +456,12 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
>>>   		       crtc_state->vrr.vmin - 1);
>>>   	intel_de_write(display, TRANS_VRR_VMAX(display, cpu_transcoder),
>>>   		       crtc_state->vrr.vmax - 1);
>>> -	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
>>> -		       trans_vrr_ctl(crtc_state));
>>> +	if (intel_vrr_always_use_vrr_tg(display))
>>> +		intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
>>> +			       VRR_CTL_VRR_ENABLE | trans_vrr_ctl(crtc_state));
>>> +	else
>>> +		intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
>>> +			       trans_vrr_ctl(crtc_state));
>> We should probably remove this VRR_CTL frobbing from here entirely,
>> and just always do it from the intel_vrr_trancoder_{enable,disable}().
>> And obviously for the !always_use_vrr_tg case we just skip setting
>> the enable bit there.
> Hmm. One thing that might screw us over here is the fastboot vs.
> vblank_delay stuff. We might have to allow that to reconfigure
> the guardband...
>
> In that case we need to reprogram VRR_CTL from
> intel_set_transcoder_timings_lrr(), and be careful what
> we do with the enable bit. So it'd perhaps have to be
> something like:
>   vrr_ctl = trans_vrr_ctl();
>   if (always_use_vrr_tg && !needs_modeset)
> 	vrr_ctl |= VRR_CTL_VRR_ENABLE;

I understand while using fastset for platforms that use vrr TG, we dont 
want to reset the VRR_ENABLE while setting the guardband.

We want to use the function intel_vrr_transcoder_enable to handle bits 
for VRR_CTL.

Do you mean to pass need_modeset flag to intel_vrr_transcoder_enable()?


Regards,

Ankit






>
> Either way we should move the guardbad and pipeline_full checks
> out from the pure !fastset block in intel_pipe_config_compare().
> And if we do need the fastboot stuff for them then we need to use
> the allow_vblank_delay_fastset() stuff for them as well.
>
>>>   	intel_de_write(display, TRANS_VRR_FLIPLINE(display, cpu_transcoder),
>>>   		       crtc_state->vrr.flipline - 1);
>>>   
>>> @@ -536,7 +540,6 @@ bool intel_vrr_is_push_sent(const struct intel_crtc_state *crtc_state)
>>>   	return intel_de_read(display, TRANS_PUSH(display, cpu_transcoder)) & TRANS_PUSH_SEND;
>>>   }
>>>   
>>> -static
>>>   bool intel_vrr_always_use_vrr_tg(struct intel_display *display)
>>>   {
>>>   	if (!HAS_VRR(display))
>>> @@ -616,6 +619,26 @@ void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
>>>   	intel_vrr_set_fixed_rr_timings(old_crtc_state);
>>>   }
>>>   
>>> +void intel_vrr_enable_fixed_rr_timings(const struct intel_crtc_state *crtc_state)
>>> +{
>>> +	struct intel_display *display = to_intel_display(crtc_state);
>>> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>>> +
>>> +	intel_vrr_set_fixed_rr_timings(crtc_state);
>>> +
>>> +	if (HAS_AS_SDP(display))
>>> +		intel_de_write(display,
>>> +			       TRANS_VRR_VSYNC(display, cpu_transcoder),
>>> +			       VRR_VSYNC_END(crtc_state->vrr.vsync_end) |
>>> +			       VRR_VSYNC_START(crtc_state->vrr.vsync_start));
>>> +
>>> +	intel_de_write(display, TRANS_PUSH(display, cpu_transcoder),
>>> +		       TRANS_PUSH_EN);
>>> +
>>> +	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
>>> +		       VRR_CTL_VRR_ENABLE | trans_vrr_ctl(crtc_state));
>>> +}
>>> +
>>>   static
>>>   bool intel_vrr_is_fixed_rr(const struct intel_crtc_state *crtc_state)
>>>   {
>>> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
>>> index 514822577e8a..9259964978b1 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_vrr.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_vrr.h
>>> @@ -12,6 +12,7 @@ struct drm_connector_state;
>>>   struct intel_atomic_state;
>>>   struct intel_connector;
>>>   struct intel_crtc_state;
>>> +struct intel_display;
>>>   struct intel_dsb;
>>>   
>>>   bool intel_vrr_is_capable(struct intel_connector *connector);
>>> @@ -35,5 +36,7 @@ int intel_vrr_vmin_vtotal(const struct intel_crtc_state *crtc_state);
>>>   int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state);
>>>   int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state);
>>>   int intel_vrr_vblank_delay(const struct intel_crtc_state *crtc_state);
>>> +bool intel_vrr_always_use_vrr_tg(struct intel_display *display);
>>> +void intel_vrr_enable_fixed_rr_timings(const struct intel_crtc_state *crtc_state);
>>>   
>>>   #endif /* __INTEL_VRR_H__ */
>>> -- 
>>> 2.45.2
>> -- 
>> Ville Syrjälä
>> Intel


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