Re: [PATCH 10/16] drm/i915/display: Use fixed_rr timings in modeset sequence

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Mar 18, 2025 at 01:05:34PM +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)
> v7: Reset trans_vrr_ctl to 0 unconditionally in
> intel_vrr_transcoder_disable(). (Ville)
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.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    | 57 ++++++++++++++++-----
>  drivers/gpu/drm/i915/display/intel_vrr.h    |  2 +
>  4 files changed, 54 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index f38c998935b9..44f4465c27e2 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"
>  
> @@ -3249,6 +3250,8 @@ 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) {
> @@ -3522,6 +3525,8 @@ 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 66afa66c66af..d4912199c3ac 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;
> -	}
> -

Seems to me that removing this is what causes the state checker woes
in BAT. I think we can leave this in, as our own computed state should
always have a valid flipline and it's only the GOP that doesn't have one.

>  	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 +605,48 @@ 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;
> +
> +	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);
> +	intel_de_write(display, TRANS_PUSH(display, cpu_transcoder), 0);
> +}
> +
>  bool intel_vrr_is_fixed_rr(const struct intel_crtc_state *crtc_state)
>  {
>  	return crtc_state->vrr.flipline &&
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
> index 65d2b0eead51..859f1dc8a6d7 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.h
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.h
> @@ -36,5 +36,7 @@ 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_is_fixed_rr(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

-- 
Ville Syrjälä
Intel