Re: [PATCH 11/17] drm/i915/dp: Refactor joiner max_bpp calculations into separate functions

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

On Fri, Sep 27, 2024 at 02:08:25PM +0530, Ankit Nautiyal wrote:
> Currently compressed max_bpp limitations for small joiner ram, big joiner
> and others are intermingled. Separate them into distinct functions to
> enhance clarity and maintainability.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 45 ++++++++++++++++++++-----
>  1 file changed, 37 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index f2a2541c1091..7db037f631f7 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -859,23 +859,52 @@ u32 intel_dp_dsc_nearest_valid_bpp(struct drm_i915_private *i915, u32 bpp, u32 p
>  	return bits_per_pixel;
>  }
>  
> +static int get_bigjoiner_interface_bits(struct intel_display *display)

I would s/get_// in the name.

> +{
> +	return DISPLAY_VER(display) >= 14 ? 36 : 24;
> +}
> +
> +static u32 bigjoiner_bw_max_bpp(struct intel_display *display, u32 mode_clock,
> +				int num_joined_pipes)
> +{
> +	struct drm_i915_private *i915 = to_i915(display->drm);
> +	int bigjoiner_interface_bits = get_bigjoiner_interface_bits(display);

You don't really need the local variable for this.

> +	int num_bigjoiners = num_joined_pipes / 2;
> +	u32 max_bpp;
> +	/* With bigjoiner multiple dsc engines are used in parallel so PPC is 2 */
> +	int ppc = 2;
> +
> +	max_bpp = i915->display.cdclk.max_cdclk_freq * ppc * bigjoiner_interface_bits /

s/i915->display./display->/

> +		  intel_dp_mode_to_fec_clock(mode_clock);
> +
> +	max_bpp *= num_bigjoiners;

This thing wasn't in the original code, so should be added separately
IMO.

> +
> +	return max_bpp;
> +}
> +
> +static u32 small_joiner_ram_max_bpp(struct intel_display *display, u32 mode_hdisplay)
> +{
> +	struct drm_i915_private *i915 = to_i915(display->drm);
> +	u32 max_bpp;
> +
> +	/* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
> +	max_bpp = small_joiner_ram_size_bits(i915) / mode_hdisplay;
> +
> +	return max_bpp;
> +}
> +
>  static
>  u32 get_max_compressed_bpp_with_joiner(struct drm_i915_private *i915,
>  				       u32 mode_clock, u32 mode_hdisplay,
>  				       int num_joined_pipes)
>  {
> +	struct intel_display *display = to_intel_display(&i915->drm);
>  	u32 max_bpp_small_joiner_ram;
>  
> -	/* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
> -	max_bpp_small_joiner_ram = small_joiner_ram_size_bits(i915) / mode_hdisplay;
> +	max_bpp_small_joiner_ram = small_joiner_ram_max_bpp(display, mode_hdisplay);
>  
>  	if (num_joined_pipes == 2) {
> -		int bigjoiner_interface_bits = DISPLAY_VER(i915) >= 14 ? 36 : 24;
> -		/* With bigjoiner multiple dsc engines are used in parallel so PPC is 2 */
> -		int ppc = 2;
> -		u32 max_bpp_bigjoiner =
> -			i915->display.cdclk.max_cdclk_freq * ppc * bigjoiner_interface_bits /
> -			intel_dp_mode_to_fec_clock(mode_clock);
> +		u32 max_bpp_bigjoiner = bigjoiner_bw_max_bpp(display, mode_clock, num_joined_pipes);
>  
>  		max_bpp_small_joiner_ram *= 2;

That multiplication should be inside small_joiner_ram_max_bpp().

>  
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel