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

Nautiyal, Ankit K ankit.k.nautiyal at intel.com
Thu Feb 20 05:31:45 UTC 2025


On 2/19/2025 8:35 PM, Ville Syrjälä wrote:
> On Wed, Feb 19, 2025 at 06:47:20PM +0530, Nautiyal, Ankit K wrote:
>> On 2/18/2025 12:04 AM, 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.
>> Alright. So will do the following changes:
>> In intel_vrr_set_transcoder:
>> -Avoid modifying VRR_CTL, currently, it disables VRR_VTL if flipline is
>> not set, and also writes guardband and other settings in VRR_CTL.
>>
>> -Instead of setting variable timings, just set the fixed timings always.
>>
>> Use separate functions for enabling/disabling VRR CTL:
>> -As suggested will create intel_vrr_transcoder_enable and
>> intel_vrr_transcoder_disable functions.
>> -These functions should handle VRR_CTL settings for platforms where TG
>> is not always used.
>> -I am thinking to call these functions based on vrr.flipline:
>>
>> if (is_enabling(vrr.flipline, old_crtc_state, new_crtc_state))
>>       intel_vrr_transcoder_enable(new_crtc_state)
>>
>> Thinking to add this in commit_pipe_post_planes() just before
>> intel_vrr_enable().
>>
>> if (is_disabling(vrr.flipline, old_crtc_state, new_crtc_state))
>>       intel_vrr_transcoder_disable(new_crtc_state)
> We want them called unconditionally from either
> intel_{enable,disable}_transcoder() or perhaps from some
> ddi encoder hook (not sure how early/late this needs to
> be done). And they should just do nothing for the
> !always_use_vrr_tg case.

Thanks for clarification.

As per bspec, VRR enable should be programmed after TRANS_DDI_FUNC_CTL 
and before TRANS_CONF and VRR disable should be programmed before 
TRANS_CONF.

So I will set them in appropriate places in the next version.

Thanks again for clearing this up.

Regards,

Ankit


>
>> Will try adding this in intel_pre_plane_update() after intel_vrr_disable().
>>
>> Please correct me if I have missed something or got something wrong.
>>
>> Regards,
>>
>> Ankit
>>
>>>> +	}
>>>>    	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.
>>>
>>>>    	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


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