Re: [PATCH 1/2] drm/dp: Define DSC bpp delta DPCD fields

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 4/20/2026 4:56 PM, Nemesa Garg wrote:
> Add DP_DSC_MAX_BPP_DELTA and related field and mask helper
> macros for RGB/YCbCr444 delta and YCbCr420 delta encoding.
>
> Signed-off-by: Nemesa Garg <nemesa.garg@intel.com>
> ---
>   include/drm/display/drm_dp.h | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
> index 8b15d3eeb716..2afd33d90a0e 100644
> --- a/include/drm/display/drm_dp.h
> +++ b/include/drm/display/drm_dp.h
> @@ -354,9 +354,15 @@
>   # define DP_DSC_20_PER_DP_DSC_SINK          (1 << 1)
>   # define DP_DSC_24_PER_DP_DSC_SINK          (1 << 2)
>   
> -#define DP_DSC_BITS_PER_PIXEL_INC           0x06F
> +#define MIN_DSC_BPP_DELTA_444 16
> +#define MIN_DSC_BPP_DELTA_420 12

I understand, you are not using 422 format, but for the sake of 
completeness, lets add the values and mask for 422 formats also.


> +#define BPP_DELTA_SHIFT_420 5


These belong to the 0x06E group.


> +
> +#define DP_DSC_MAX_BPP_DELTA			0x06E


To match with the DP spec name add VERSION_1 suffix.

There might be support for Version 2 in future, (atleast the DPCD 0x68 
MAX_BPP_DELTA_VERSION points to that).


>   # define DP_DSC_RGB_YCbCr444_MAX_BPP_DELTA_MASK 0x1f
>   # define DP_DSC_RGB_YCbCr420_MAX_BPP_DELTA_MASK 0xe0


These bits were wrongly grouped with DPCD 0x06F. This correction should 
be a separate patch.


Regards,

Ankit

> +
> +#define DP_DSC_BITS_PER_PIXEL_INC           0x06F
>   # define DP_DSC_BITS_PER_PIXEL_1_16         0x0
>   # define DP_DSC_BITS_PER_PIXEL_1_8          0x1
>   # define DP_DSC_BITS_PER_PIXEL_1_4          0x2