Re: [PATCH 11/15] drm/i915/display: Refactor enable_joiner_pipes

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

On Wed, Sep 18, 2024 at 08:13:39PM +0530, Ankit Nautiyal wrote:
> Pass the current pipe into enabled_joiner_pipes(), and let it figure out
> the proper bitmasks for us.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 58 +++++++++++++-------
>  1 file changed, 39 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 1ce334f3a3ae..65119c26ec88 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -3717,7 +3717,19 @@ static void enabled_ultrajoiner_pipes(struct drm_i915_private *i915,
>  	}
>  }
>  
> -static void enabled_joiner_pipes(struct drm_i915_private *dev_priv,
> +static enum pipe get_joiner_primary_pipe(enum pipe pipe, u8 primary_pipes, u8 secondary_pipes)
> +{
> +	if ((secondary_pipes & BIT(pipe)) == 0)
> +		return pipe;
> +
> +	/* ignore everything above our pipe */
> +	primary_pipes &= ~GENMASK(7, pipe);
> +
> +	/* highest remaining bit should be our primary pipe */
> +	return fls(primary_pipes) - 1;

I think this could now be simplified to something like:

{
	primary_pipes &= GENMASK(pipe, 0);

	return primary_pipes ? BIT(fls(primary_pipes) - 1) : 0;
}

And returning a bitmask like that would perhaps be easier
for enabled_joiner_pipes() to handle.

> +}
> +
> +static void enabled_joiner_pipes(struct drm_i915_private *dev_priv, enum pipe pipe,
>  				 u8 *primary_pipes, u8 *secondary_pipes)
>  {
>  	struct intel_display *display = to_intel_display(&dev_priv->drm);
> @@ -3782,10 +3794,30 @@ static void enabled_joiner_pipes(struct drm_i915_private *dev_priv,
>  		 expected_ultrajoiner_secondary_pipes(primary_ultrajoiner_pipes),
>  		 secondary_ultrajoiner_pipes);
>  
> -	*primary_pipes = primary_uncompressed_joiner_pipes | primary_bigjoiner_pipes |
> -			 primary_ultrajoiner_pipes;
> -	*secondary_pipes = secondary_uncompressed_joiner_pipes | secondary_bigjoiner_pipes |
> -			 secondary_ultrajoiner_pipes;
> +	*primary_pipes = 0;
> +	*secondary_pipes = 0;
> +
> +	if (ultrajoiner_pipes & BIT(pipe)) {
> +		*primary_pipes = BIT(get_joiner_primary_pipe(pipe, primary_ultrajoiner_pipes,
> +							     secondary_ultrajoiner_pipes));
> +		*secondary_pipes = secondary_ultrajoiner_pipes &
> +				   expected_ultrajoiner_secondary_pipes(primary_ultrajoiner_pipes);
> +		return;
> +	}
> +
> +	if (uncompressed_joiner_pipes & BIT(pipe)) {
> +		*primary_pipes = BIT(get_joiner_primary_pipe(pipe,
> +							     primary_uncompressed_joiner_pipes,
> +							     secondary_uncompressed_joiner_pipes));
> +		*secondary_pipes =
> +			secondary_uncompressed_joiner_pipes &
> +			expected_uncompjoiner_secondary_pipes(primary_uncompressed_joiner_pipes);
> +	} else if (bigjoiner_pipes & BIT(pipe)) {
> +		*primary_pipes = BIT(get_joiner_primary_pipe(pipe, primary_bigjoiner_pipes,
> +							     secondary_bigjoiner_pipes));
> +		*secondary_pipes = secondary_bigjoiner_pipes &
> +				   expected_bigjoiner_secondary_pipes(primary_bigjoiner_pipes);
> +	}
>  
>  	/* Joiner pipes should always be consecutive primary and secondary */
>  	drm_WARN(display->drm, *secondary_pipes != *primary_pipes << 1,

This would now have to be something like:
drm_WARN(expected_*_secondary_pipes(*primary_pipes) != *secondary_pipes);
(wich I suppose manes it has to be done for each joiner type
separately.

> @@ -3793,18 +3825,6 @@ static void enabled_joiner_pipes(struct drm_i915_private *dev_priv,
>  		 *primary_pipes, *secondary_pipes);
>  }
>  
> -static enum pipe get_joiner_primary_pipe(enum pipe pipe, u8 primary_pipes, u8 secondary_pipes)
> -{
> -	if ((secondary_pipes & BIT(pipe)) == 0)
> -		return pipe;
> -
> -	/* ignore everything above our pipe */
> -	primary_pipes &= ~GENMASK(7, pipe);
> -
> -	/* highest remaining bit should be our primary pipe */
> -	return fls(primary_pipes) - 1;
> -}
> -
>  static u8 get_joiner_secondary_pipes(enum pipe pipe, u8 primary_pipes, u8 secondary_pipes)
>  {
>  	enum pipe primary_pipe, next_primary_pipe;

I think this guy could be nuked, and callers should just use the
bitmasks returned by enabled_joiner_pipes directly.

> @@ -3893,7 +3913,7 @@ static u8 hsw_enabled_transcoders(struct intel_crtc *crtc)
>  		enabled_transcoders |= BIT(cpu_transcoder);
>  
>  	/* joiner secondary -> consider the primary pipe's transcoder as well */
> -	enabled_joiner_pipes(dev_priv, &primary_pipes, &secondary_pipes);
> +	enabled_joiner_pipes(dev_priv, crtc->pipe, &primary_pipes, &secondary_pipes);
>  	if (secondary_pipes & BIT(crtc->pipe)) {
>  		cpu_transcoder = (enum transcoder)
>  			get_joiner_primary_pipe(crtc->pipe, primary_pipes, secondary_pipes);
> @@ -4030,7 +4050,7 @@ static void intel_joiner_get_config(struct intel_crtc_state *crtc_state)
>  	u8 primary_pipes, secondary_pipes;
>  	enum pipe pipe = crtc->pipe;
>  
> -	enabled_joiner_pipes(i915, &primary_pipes, &secondary_pipes);
> +	enabled_joiner_pipes(i915, pipe, &primary_pipes, &secondary_pipes);
>  
>  	if (((primary_pipes | secondary_pipes) & BIT(pipe)) == 0)
>  		return;
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel