Re: [PATCH v2 1/3] drm/i915: Make ips_enabled a property depending on whether IPS is enabled, v2.

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

On Mon, Nov 20, 2017 at 01:23:35PM +0100, Maarten Lankhorst wrote:
> ips_enabled was used as a variable of whether IPS can be enabled or not,
> but should be used to test whether IPS is actually enabled.
> 
> Changes since v1:
> - Call needs_modeset on new crtc state. (Ville)
> - IPS can be enabled with sprite plane enabled too. (Ville)
> - Fix CDCLK vs IPS workaround. (Ville)
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_cdclk.c    |   2 +-
>  drivers/gpu/drm/i915/intel_display.c  | 119 +++++++++++++++++++---------------
>  drivers/gpu/drm/i915/intel_drv.h      |   1 +
>  drivers/gpu/drm/i915/intel_pipe_crc.c |   2 -
>  4 files changed, 67 insertions(+), 57 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
> index e8884c2ade98..30affa7903d7 100644
> --- a/drivers/gpu/drm/i915/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> @@ -1896,7 +1896,7 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state)
>  	min_cdclk = intel_pixel_rate_to_cdclk(dev_priv, crtc_state->pixel_rate);
>  
>  	/* pixel rate mustn't exceed 95% of cdclk with IPS on BDW */
> -	if (IS_BROADWELL(dev_priv) && crtc_state->ips_enabled)
> +	if (IS_BROADWELL(dev_priv) && hsw_pipe_config_ips_capable(crtc_state))
>  		min_cdclk = DIV_ROUND_UP(min_cdclk * 100, 95);

I think either we should drop this entirely and make the
ips_compute_config() check logical.cdclk instead of max_cdclk,
or we stick to the max_cdclk based check but move it into 
hsw_pipe_config_ips_capable(). Otherwise we would end up
rejecting any mode whose pixel rate exceed the 95% cdclk
limit.

>  
>  	/* BSpec says "Do not use DisplayPort with CDCLK less than 432 MHz,
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 3b3dec1e6640..0b9ba415839a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4870,7 +4870,7 @@ void hsw_enable_ips(const struct intel_crtc_state *crtc_state)
>  	struct drm_device *dev = crtc->base.dev;
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  
> -	if (!crtc->config->ips_enabled)
> +	if (!crtc_state->ips_enabled)
>  		return;
>  
>  	/*
> @@ -4966,14 +4966,6 @@ intel_post_enable_primary(struct drm_crtc *crtc,
>  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
>  	int pipe = intel_crtc->pipe;
>  
> -	/*
> -	 * FIXME IPS should be fine as long as one plane is
> -	 * enabled, but in practice it seems to have problems
> -	 * when going from primary only to sprite only and vice
> -	 * versa.
> -	 */
> -	hsw_enable_ips(new_crtc_state);
> -
>  	/*
>  	 * Gen2 reports pipe underruns whenever all planes are disabled.
>  	 * So don't enable underrun reporting before at least some planes
> @@ -4989,10 +4981,9 @@ intel_post_enable_primary(struct drm_crtc *crtc,
>  	intel_check_pch_fifo_underruns(dev_priv);
>  }
>  
> -/* FIXME move all this to pre_plane_update() with proper state tracking */
> +/* FIXME get rid of this and use pre_plane_update */
>  static void
> -intel_pre_disable_primary(struct drm_crtc *crtc,
> -			  const struct intel_crtc_state *old_crtc_state)
> +intel_pre_disable_primary_noatomic(struct drm_crtc *crtc)
>  {
>  	struct drm_device *dev = crtc->dev;
>  	struct drm_i915_private *dev_priv = to_i915(dev);
> @@ -5001,32 +4992,12 @@ intel_pre_disable_primary(struct drm_crtc *crtc,
>  
>  	/*
>  	 * Gen2 reports pipe underruns whenever all planes are disabled.
> -	 * So diasble underrun reporting before all the planes get disabled.
> -	 * FIXME: Need to fix the logic to work when we turn off all planes
> -	 * but leave the pipe running.
> +	 * So disable underrun reporting before all the planes get disabled.
>  	 */
>  	if (IS_GEN2(dev_priv))
>  		intel_set_cpu_fifo_underrun_reporting(dev_priv, pipe, false);
>  
> -	/*
> -	 * FIXME IPS should be fine as long as one plane is
> -	 * enabled, but in practice it seems to have problems
> -	 * when going from primary only to sprite only and vice
> -	 * versa.
> -	 */
> -	hsw_disable_ips(old_crtc_state);
> -}
> -
> -/* FIXME get rid of this and use pre_plane_update */
> -static void
> -intel_pre_disable_primary_noatomic(struct drm_crtc *crtc)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	struct drm_i915_private *dev_priv = to_i915(dev);
> -	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> -	int pipe = intel_crtc->pipe;
> -
> -	intel_pre_disable_primary(crtc, to_intel_crtc_state(crtc->state));
> +	hsw_disable_ips(to_intel_crtc_state(crtc->state));
>  
>  	/*
>  	 * Vblank time updates from the shadow to live plane control register
> @@ -5058,6 +5029,11 @@ static void intel_post_plane_update(struct intel_crtc_state *old_crtc_state)
>  	if (pipe_config->update_wm_post && pipe_config->base.active)
>  		intel_update_watermarks(crtc);
>  
> +	if (!old_crtc_state->ips_enabled ||
> +	    needs_modeset(&pipe_config->base) ||
> +	    pipe_config->update_pipe)

Hmm. So thinking more about this I guess I figured out why you put the
update_pipe check here. On BDW the initial old_crtc_state will have
ips_enabled=true since the readout now always makes it so. Thus if we
skip the initial modeset we would not turn on IPS even if a suitable
set of planes is enabled.

I think it would be more clear to check for the INHERITED thing
specifically. Also that would avoid paying the cost of the pcode
access every time we have update_pipe==true and ips_enabled==true.

> +		hsw_enable_ips(pipe_config);
> +
>  	if (old_pri_state) {
>  		struct intel_plane_state *primary_state =
>  			intel_atomic_get_new_plane_state(to_intel_atomic_state(old_state),
> @@ -5088,6 +5064,9 @@ static void intel_pre_plane_update(struct intel_crtc_state *old_crtc_state,
>  	struct intel_atomic_state *old_intel_state =
>  		to_intel_atomic_state(old_state);
>  
> +	if (needs_modeset(&pipe_config->base) || !pipe_config->ips_enabled)
> +		hsw_disable_ips(old_crtc_state);
> +
>  	if (old_pri_state) {
>  		struct intel_plane_state *primary_state =
>  			intel_atomic_get_new_plane_state(old_intel_state,
> @@ -5096,10 +5075,13 @@ static void intel_pre_plane_update(struct intel_crtc_state *old_crtc_state,
>  			to_intel_plane_state(old_pri_state);
>  
>  		intel_fbc_pre_update(crtc, pipe_config, primary_state);
> -
> -		if (old_primary_state->base.visible &&
> +		/*
> +		 * Gen2 reports pipe underruns whenever all planes are disabled.
> +		 * So disable underrun reporting before all the planes get disabled.
> +		 */
> +		if (IS_GEN2(dev_priv) && old_primary_state->base.visible &&
>  		    (modeset || !primary_state->base.visible))
> -			intel_pre_disable_primary(&crtc->base, old_crtc_state);
> +			intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, false);
>  	}
>  
>  	/*
> @@ -6228,15 +6210,42 @@ static int ironlake_fdi_compute_config(struct intel_crtc *intel_crtc,
>  	return ret;
>  }
>  
> -static bool pipe_config_supports_ips(struct drm_i915_private *dev_priv,
> -				     struct intel_crtc_state *pipe_config)
> +bool hsw_pipe_config_ips_capable(const struct intel_crtc_state *pipe_config)
>  {
> -	if (pipe_config->ips_force_disable)
> +	struct intel_crtc *crtc = to_intel_crtc(pipe_config->base.crtc);
> +
> +	/* IPS only exists on ULT machines and is tied to pipe A. */
> +	if (!hsw_crtc_supports_ips(crtc))
> +		return false;
> +
> +	if (!i915_modparams.enable_ips)
>  		return false;
>  
>  	if (pipe_config->pipe_bpp > 24)
>  		return false;
>  
> +	return true;
> +}
> +
> +static bool hsw_compute_ips_config(struct intel_crtc_state *pipe_config)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(pipe_config->base.crtc->dev);
> +
> +	if (!hsw_pipe_config_ips_capable(pipe_config))
> +		return false;
> +
> +	if (pipe_config->ips_force_disable)
> +		return false;
> +
> +	/*
> +	 * FIXME IPS should be fine as long as one plane is
> +	 * enabled, but in practice it seems to have problems
> +	 * when going from primary only to sprite only and vice
> +	 * versa.
> +	 */
> +	if (!(pipe_config->active_planes & BIT(PLANE_PRIMARY)))
> +		return false;
> +
>  	/* HSW can handle pixel rate up to cdclk? */
>  	if (IS_HASWELL(dev_priv))
>  		return true;
> @@ -6252,17 +6261,6 @@ static bool pipe_config_supports_ips(struct drm_i915_private *dev_priv,
>  		dev_priv->max_cdclk_freq * 95 / 100;
>  }
>  
> -static void hsw_compute_ips_config(struct intel_crtc *crtc,
> -				   struct intel_crtc_state *pipe_config)
> -{
> -	struct drm_device *dev = crtc->base.dev;
> -	struct drm_i915_private *dev_priv = to_i915(dev);
> -
> -	pipe_config->ips_enabled = i915_modparams.enable_ips &&
> -		hsw_crtc_supports_ips(crtc) &&
> -		pipe_config_supports_ips(dev_priv, pipe_config);
> -}
> -
>  static bool intel_crtc_supports_double_wide(const struct intel_crtc *crtc)
>  {
>  	const struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> @@ -6378,9 +6376,6 @@ static int intel_crtc_compute_config(struct intel_crtc *crtc,
>  
>  	intel_crtc_compute_pixel_rate(pipe_config);
>  
> -	if (HAS_IPS(dev_priv))
> -		hsw_compute_ips_config(crtc, pipe_config);
> -
>  	if (pipe_config->has_pch_encoder)
>  		return ironlake_fdi_compute_config(crtc, pipe_config);
>  
> @@ -9275,6 +9270,19 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
>  			ironlake_get_pfit_config(crtc, pipe_config);
>  	}
>  
> +	if (hsw_crtc_supports_ips(crtc)) {
> +		if (IS_HASWELL(dev_priv))
> +			pipe_config->ips_enabled = I915_READ(IPS_CTL) & IPS_ENABLE;
> +		else {
> +			/*
> +			 * We cannot readout IPS state on broadwell, set to
> +			 * true so we can set it to a defined state on first
> +			 * commit.
> +			 */
> +			pipe_config->ips_enabled = true;
> +		}
> +	}
> +
>  	if (pipe_config->cpu_transcoder != TRANSCODER_EDP &&
>  	    !transcoder_is_dsi(pipe_config->cpu_transcoder)) {
>  		pipe_config->pixel_multiplier =
> @@ -10488,6 +10496,9 @@ static int intel_crtc_atomic_check(struct drm_crtc *crtc,
>  							 pipe_config);
>  	}
>  
> +	if (HAS_IPS(dev_priv))
> +		pipe_config->ips_enabled = hsw_compute_ips_config(pipe_config);
> +
>  	return ret;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 69aab324aaa1..40417b20844e 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1485,6 +1485,7 @@ bool bxt_find_best_dpll(struct intel_crtc_state *crtc_state, int target_clock,
>  int chv_calc_dpll_params(int refclk, struct dpll *pll_clock);
>  
>  bool intel_crtc_active(struct intel_crtc *crtc);
> +bool hsw_pipe_config_ips_capable(const struct intel_crtc_state *pipe_config);
>  void hsw_enable_ips(const struct intel_crtc_state *crtc_state);
>  void hsw_disable_ips(const struct intel_crtc_state *crtc_state);
>  enum intel_display_power_domain intel_port_to_power_domain(enum port port);
> diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
> index 61641d479b93..1f5cd572a7ff 100644
> --- a/drivers/gpu/drm/i915/intel_pipe_crc.c
> +++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
> @@ -541,8 +541,6 @@ static void hsw_pipe_A_crc_wa(struct drm_i915_private *dev_priv,
>  		 * completely disable it.
>  		 */
>  		pipe_config->ips_force_disable = enable;
> -		if (pipe_config->ips_enabled == enable)
> -			pipe_config->base.connectors_changed = true;
>  	}
>  
>  	if (IS_HASWELL(dev_priv)) {
> -- 
> 2.15.0
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx