[Intel-gfx] [PATCH 07/11] drm/i915/display/vrr: Configure and enable VRR in modeset enable

[Jani Nikula]

On Thu, 22 Oct 2020, Manasi Navare <manasi.d.navare at intel.com> wrote:
> This patch computes the VRR parameters from VRR crtc states
> and configures them in VRR registers during CRTC enable in
> the modeset enable sequence.
>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c |  5 ++++
>  drivers/gpu/drm/i915/display/intel_vrr.c | 38 ++++++++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_vrr.h |  2 ++
>  3 files changed, 45 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 09811be08cfe..391c51979334 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -49,6 +49,7 @@
>  #include "intel_sprite.h"
>  #include "intel_tc.h"
>  #include "intel_vdsc.h"
> +#include "intel_vrr.h"
>  
>  struct ddi_buf_trans {
>  	u32 trans1;	/* balance leg enable, de-emph level */
> @@ -4046,6 +4047,10 @@ static void intel_enable_ddi(struct intel_atomic_state *state,
>  
>  	intel_ddi_enable_transcoder_func(encoder, crtc_state);
>  
> +	/* Enable VRR if requested through CRTC property */

I don't think the comment is helpful, really.

> +	if (crtc_state->vrr.enable)
> +		intel_vrr_enable(encoder, crtc_state);

In the disable path you check the vrr.enable within the
function. Perhaps we should do the same here, i.e. call vrr enable
unconditionally and have it early return if not requested.

> +
>  	intel_enable_pipe(crtc_state);
>  
>  	intel_crtc_vblank_on(crtc_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 56114f535f94..7f1353bac583 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -64,3 +64,41 @@ intel_vrr_compute_config(struct intel_dp *intel_dp,
>  		 crtc_state->vrr.vtotalmax);
>  }
>  
> +void intel_vrr_enable(struct intel_encoder *encoder,
> +		      const struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	enum pipe pipe = crtc->pipe;
> +	const struct drm_display_mode *adjusted_mode =
> +		&crtc_state->hw.adjusted_mode;
> +	u32 trans_vrr_ctl = 0, trans_vrr_vmax = 0, trans_vrr_vmin = 0, trans_vrr_flipline = 0, trans_push = 0;
> +	u16 framestart_to_pipelinefull_linecnt = 0;

All the initializations to 0 are unnecessary.

> +
> +	framestart_to_pipelinefull_linecnt =
> +		min_t(u16, 255, (crtc_state->vrr.vtotalmin - adjusted_mode->crtc_vdisplay));
> +
> +	trans_vrr_ctl = VRR_CTL_VRR_ENABLE |  VRR_CTL_IGN_MAX_SHIFT |
> +		VRR_CTL_FLIP_LINE_EN | VRR_CTL_LINE_COUNT(framestart_to_pipelinefull_linecnt) |
> +		VRR_CTL_SW_FULLLINE_COUNT;
> +
> +	/* Programming adjustments for 0 based regs */
> +	trans_vrr_vmax = crtc_state->vrr.vtotalmax - 1;
> +	trans_vrr_vmin = crtc_state->vrr.vtotalmin - 1;
> +	trans_vrr_flipline = crtc_state->vrr.vtotalmin - 1;
> +
> +	trans_push = TRANS_PUSH_EN;

Frankly I'd just throw away the above four temp variables.

> +
> +	intel_de_write(dev_priv, TRANS_VRR_VMIN(pipe), trans_vrr_vmin);
> +	intel_de_write(dev_priv, TRANS_VRR_VMAX(pipe), trans_vrr_vmax);
> +	intel_de_write(dev_priv, TRANS_VRR_CTL(pipe), trans_vrr_ctl);
> +	intel_de_write(dev_priv, TRANS_VRR_FLIPLINE(pipe), trans_vrr_flipline);
> +	intel_de_write(dev_priv, TRANS_PUSH(pipe), trans_push);
> +
> +	drm_dbg(&dev_priv->drm,	"Enabling VRR on pipe (%c)\n", pipe_name(pipe));

drm_dbg_kms. "pipe %c" is the convention, not "pipe (%c)".

> +	drm_dbg(&dev_priv->drm, "VRR Parameters: Vblank - Min = %d, Max = %d Flipline Count = %d, CTL Reg = 0x%08x, TRANS PUSH reg = 0x%08x",
> +		crtc_state->vrr.vtotalmin, crtc_state->vrr.vtotalmax,
> +		crtc_state->vrr.vtotalmin, trans_vrr_ctl,
> +		trans_push);
> +}
> +
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
> index 1e6fe8fe92ec..05d982d6fbae 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.h
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.h
> @@ -17,5 +17,7 @@ struct intel_dp;
>  bool intel_is_vrr_capable(struct drm_connector *connector);
>  void intel_vrr_compute_config(struct intel_dp *intel_dp,
>  			      struct intel_crtc_state *crtc_state);
> +void intel_vrr_enable(struct intel_encoder *encoder,
> +		      const struct intel_crtc_state *crtc_state);
>  
>  #endif /* __INTEL_VRR_H__ */

-- 
Jani Nikula, Intel Open Source Graphics Center