Re: [PATCH 15/21] drm/i915/display: Use fixed_rr timings in modeset sequence

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 3/6/2025 10:16 PM, Ville Syrjälä wrote:
> On Thu, Mar 06, 2025 at 06:40:54PM +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.
>>
>> For this intel_vrr_set_transcoder now always programs fixed timings.
>> Later if vrr timings are required, vrr_enable() will switch
>> to the real VRR timings.
>>
>> For platforms that will always use VRR TG, the VRR_CTL Enable bit is set
>> and reset in the transcoder enable/disable path.
>>
>> v2: Update intel_vrr_set_transcoder_timings for fixed_rr.
>> v3: Update intel_set_transcoder_timings_lrr for fixed_rr. (Ville)
>> v4: Have separate functions to enable/disable VRR CTL
>> v5:
>> -For platforms that do not always have VRRTG on, do write bits other
>> than enable bit and also use write the TRANS_VRR_PUSH register. (Ville)
>> -Avoid writing trans_ctl_vrr if !vrr_possible().
>> v6:
>> -Disable VRR just before intel_ddi_disable_transcoder_func(). (Ville)
>> -Correct the sequence of configuring PUSH and VRR Enable/Disable. (Ville)
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_ddi.c    |  5 ++
>>   drivers/gpu/drm/i915/display/intel_dp_mst.c |  4 ++
>>   drivers/gpu/drm/i915/display/intel_vrr.c    | 63 ++++++++++++++++-----
>>   drivers/gpu/drm/i915/display/intel_vrr.h    |  2 +
>>   4 files changed, 60 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
>> index 676c1826f15c..6d89a87b3419 100644
>> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
>> @@ -78,6 +78,7 @@
>>   #include "intel_tc.h"
>>   #include "intel_vdsc.h"
>>   #include "intel_vdsc_regs.h"
>> +#include "intel_vrr.h"
>>   #include "skl_scaler.h"
>>   #include "skl_universal_plane.h"
>>   
>> @@ -3248,6 +3249,8 @@ static void intel_ddi_post_disable_hdmi_or_sst(struct intel_atomic_state *state,
>>   		drm_dp_dpcd_poll_act_handled(&intel_dp->aux, 0);
>>   	}
>>   
>> +	intel_vrr_transcoder_disable(old_crtc_state);
>> +
>>   	intel_ddi_disable_transcoder_func(old_crtc_state);
>>   
>>   	for_each_pipe_crtc_modeset_disable(display, pipe_crtc, old_crtc_state, i) {
>> @@ -3521,6 +3524,8 @@ static void intel_ddi_enable(struct intel_atomic_state *state,
>>   
>>   	intel_ddi_enable_transcoder_func(encoder, crtc_state);
>>   
>> +	intel_vrr_transcoder_enable(crtc_state);
>> +
>>   	/* Enable/Disable DP2.0 SDP split config before transcoder */
>>   	intel_audio_sdp_split_update(crtc_state);
>>   
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> index bd47cf127b4c..d2988b9a6e7b 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> @@ -1065,6 +1065,8 @@ static void mst_stream_post_disable(struct intel_atomic_state *state,
>>   	drm_dp_remove_payload_part2(&intel_dp->mst.mgr, new_mst_state,
>>   				    old_payload, new_payload);
>>   
>> +	intel_vrr_transcoder_disable(old_crtc_state);
>> +
>>   	intel_ddi_disable_transcoder_func(old_crtc_state);
>>   
>>   	for_each_pipe_crtc_modeset_disable(display, pipe_crtc, old_crtc_state, i) {
>> @@ -1326,6 +1328,8 @@ static void mst_stream_enable(struct intel_atomic_state *state,
>>   
>>   	intel_ddi_enable_transcoder_func(encoder, pipe_config);
>>   
>> +	intel_vrr_transcoder_enable(pipe_config);
>> +
>>   	intel_ddi_clear_act_sent(encoder, pipe_config);
>>   
>>   	intel_de_rmw(display, TRANS_DDI_FUNC_CTL(display, trans), 0,
>> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
>> index f523a48e6186..d7580b6e4e37 100644
>> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
>> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
>> @@ -460,12 +460,6 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
>>   		intel_de_rmw(display, CHICKEN_TRANS(display, cpu_transcoder),
>>   			     0, PIPE_VBLANK_WITH_DELAY);
>>   
>> -	if (!intel_vrr_possible(crtc_state)) {
>> -		intel_de_write(display,
>> -			       TRANS_VRR_CTL(display, cpu_transcoder), 0);
>> -		return;
>> -	}
>> -
>>   	if (crtc_state->cmrr.enable) {
>>   		intel_de_write(display, TRANS_CMRR_M_HI(display, cpu_transcoder),
>>   			       upper_32_bits(crtc_state->cmrr.cmrr_m));
>> @@ -477,14 +471,7 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
>>   			       lower_32_bits(crtc_state->cmrr.cmrr_n));
>>   	}
>>   
>> -	intel_de_write(display, TRANS_VRR_VMIN(display, cpu_transcoder),
>> -		       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));
>> -	intel_de_write(display, TRANS_VRR_FLIPLINE(display, cpu_transcoder),
>> -		       crtc_state->vrr.flipline - 1);
>> +	intel_vrr_set_fixed_rr_timings(crtc_state);
>>   
>>   	if (HAS_AS_SDP(display))
>>   		intel_de_write(display,
>> @@ -618,6 +605,54 @@ void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
>>   	intel_vrr_set_fixed_rr_timings(old_crtc_state);
>>   }
>>   
>> +void intel_vrr_transcoder_enable(const struct intel_crtc_state *crtc_state)
>> +{
>> +	struct intel_display *display = to_intel_display(crtc_state);
>> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>> +
>> +	if (!HAS_VRR(display))
>> +		return;
>> +
>> +	if (!intel_vrr_possible(crtc_state))
>> +		return;
>> +
>> +	if (!intel_vrr_always_use_vrr_tg(display)) {
>> +		intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
>> +			       trans_vrr_ctl(crtc_state));
>> +		return;
>> +	}
>> +
>> +	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));
>> +}
>> +
>> +void intel_vrr_transcoder_disable(const struct intel_crtc_state *crtc_state)
>> +{
>> +	struct intel_display *display = to_intel_display(crtc_state);
>> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>> +
>> +	if (!HAS_VRR(display))
>> +		return;
>> +
>> +	if (!intel_vrr_possible(crtc_state))
>> +		return;
>> +
>> +	if (!intel_vrr_always_use_vrr_tg(display)) {
>> +		intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
>> +			       trans_vrr_ctl(crtc_state));
> IMO we should write 0 here too.

There is one problem. If we do not write trans_vrr_ctl but crtc_state 
has flipline, vmin, vmax all set to some value, then we get mismatch in 
vrr_get_config.

Currently we are reading out vrr.flipline/vmax/vmin only if VRR_CTL has 
VRR_CTL_FLIP_LINE_EN as set.

Also, I think we need to write trans_vrr_ctl in 
intel_vrr_set_transcoder_timings(). Currently that is removed.

Mismatch is also seen where the platform has only eDP connected and we 
just do fastset. In that case intel_vrr_transcoder_enable(). doesnt get 
call and we get a mismatch.


>
>> +		return;
>> +	}
>> +
>> +	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder), 0);
>> +
>> +	intel_de_wait_for_clear(display, TRANS_VRR_STATUS(display, cpu_transcoder),
>> +				VRR_STATUS_VRR_EN_LIVE, 1000);
> Does this do anything? I would have thought the VRR live status would
> clear already earlier when we disable the transcoder?

Hmm, in Bspec:68925 it seems its mentioned to wait for VRR live status 
and then clear the VRR PUSH_ENABLE.

But not sure if it applies if we are disable the transcoder.

Regards,

Ankit

>
>> +	intel_de_write(display, TRANS_PUSH(display, cpu_transcoder), 0);
>> +}
>> +
>>   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..c4ee8a758e19 100644
>> --- a/drivers/gpu/drm/i915/display/intel_vrr.h
>> +++ b/drivers/gpu/drm/i915/display/intel_vrr.h
>> @@ -35,5 +35,7 @@ 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);
>> +void intel_vrr_transcoder_enable(const struct intel_crtc_state *crtc_state);
>> +void intel_vrr_transcoder_disable(const struct intel_crtc_state *crtc_state);
>>   
>>   #endif /* __INTEL_VRR_H__ */
>> -- 
>> 2.45.2