Re: [PATCH 17/20] drm/i915/display: Use fixed_rr timings in modeset sequence

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

On Mon, Feb 24, 2025 at 11:47:14AM +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
> 
> 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    | 40 +++++++++++++--------
>  drivers/gpu/drm/i915/display/intel_vrr.h    |  3 ++
>  4 files changed, 38 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 5082f38b0a02..8863d1526aea 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -77,6 +77,7 @@
>  #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"
>  
> @@ -3276,6 +3277,8 @@ static void intel_ddi_post_disable(struct intel_atomic_state *state,
>  				   const struct intel_crtc_state *old_crtc_state,
>  				   const struct drm_connector_state *old_conn_state)
>  {
> +	intel_vrr_transcoder_disable(old_crtc_state);
> +
>  	if (!intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_DP_MST))
>  		intel_ddi_post_disable_hdmi_or_sst(state, encoder, old_crtc_state,
>  						   old_conn_state);
> @@ -3524,6 +3527,8 @@ 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 2c4a9ac6f61e..5ec353eceab4 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -1048,6 +1048,8 @@ static void mst_stream_post_disable(struct intel_atomic_state *state,
>  		intel_crtc_vblank_off(old_pipe_crtc_state);
>  	}
>  
> +	intel_vrr_transcoder_disable(old_crtc_state);
> +
>  	intel_disable_transcoder(old_crtc_state);
>  
>  	drm_dp_remove_payload_part1(&intel_dp->mst_mgr, new_mst_state, new_payload);
> @@ -1325,6 +1327,8 @@ 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 e77f5b483b09..551dcc16f0d4 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -434,6 +434,7 @@ void intel_vrr_set_transcoder_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;
> +	bool needs_modeset = intel_crtc_needs_modeset(crtc_state);
>  
>  	if (intel_crtc_is_joiner_secondary(crtc_state))
>  		return;
> @@ -447,12 +448,6 @@ 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));
> @@ -464,14 +459,8 @@ 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);
> +	intel_vrr_update_guardband(crtc_state, needs_modeset);
>  
>  	if (HAS_AS_SDP(display))
>  		intel_de_write(display,
> @@ -614,6 +603,29 @@ 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 (!intel_vrr_always_use_vrr_tg(display))
> +		return;
> +
> +	intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
> +		       VRR_CTL_VRR_ENABLE | trans_vrr_ctl(crtc_state));

Hmm. Maybe we should actually program this even for the
!intel_vrr_always_use_vrr_tg() case, but just leave the enable
bit unset. That way we shouldn't need the intel_vrr_update_guardband()
stuff in vrr_set_transcoder_timings().

We'd still need something for the _lrr() case, but I think that
could simply call intel_vrr_transcoder_enable() as well.

> +}
> +
> +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 (!intel_vrr_always_use_vrr_tg(display))
> +		return;

And if we do the change to the enable() path, then we should probably
also do this for the !intel_vrr_always_use_vrr_tg() in the name of 
symmetry.

> +
> +	intel_de_write(display, TRANS_VRR_CTL(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 e4e9cadcdf9e..750a380da9e3 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);
> @@ -37,5 +38,7 @@ 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_update_guardband(const struct intel_crtc_state *crtc_state, bool needs_modeset);
>  void intel_vrr_set_fixed_rr_timings(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