[Intel-gfx] [PATCH v2 1/2] drm/i915/dp: Update Bigjoiner interface bits for computing compressed bpp

[Ville Syrjälä]

On Wed, Mar 29, 2023 at 02:37:45PM +0530, Ankit Nautiyal wrote:
> In Bigjoiner check for DSC, bigjoiner interface bits for DP for
> DISPLAY > 13 is 36 (Bspec: 49259).
> 
> v2: Corrected Display ver to 13.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index da1c00ee92fb..0b59c1e53678 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -756,8 +756,9 @@ u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private *i915,
>  	bits_per_pixel = min(bits_per_pixel, max_bpp_small_joiner_ram);
>  
>  	if (bigjoiner) {
> +		int bigjoiner_interface_bits = DISPLAY_VER(i915) <= 13 ? 24 : 36;

We generally prefer "new -> old" order. So please flip that around.

>  		u32 max_bpp_bigjoiner =
> -			i915->display.cdclk.max_cdclk_freq * 48 /
> +			i915->display.cdclk.max_cdclk_freq * 2 * bigjoiner_interface_bits /
>  			intel_dp_mode_to_fec_clock(mode_clock);

Hmm. Why is this using the FEC adjusted clock here?

>  
>  		bits_per_pixel = min(bits_per_pixel, max_bpp_bigjoiner);
> -- 
> 2.25.1

-- 
Ville Syrjälä
Intel