Re: [PATCH 2/3] drm/dp: Add max bpp delta computation constants

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

On 4/23/2026 8:00 PM, Nemesa Garg wrote:
> These constants are used when decoding dsc max delta

This seems to be missing some part. It is not clear that which constants 
are we talking about.


> values from the sink dpcd. Also add version_1 as suffix
> to MAX_DELTA_BPP.
>
> v2: Move constants under 0x6E register. [Ankit]
>      Add mask for Native 422 also. [Ankit]
>
> Signed-off-by: Nemesa Garg <nemesa.garg@intel.com>
> ---
>   include/drm/display/drm_dp.h | 23 ++++++++++++++---------
>   1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
> index 520490ac6778..c29b391453cd 100644
> --- a/include/drm/display/drm_dp.h
> +++ b/include/drm/display/drm_dp.h
> @@ -354,17 +354,22 @@
>   # define DP_DSC_20_PER_DP_DSC_SINK          (1 << 1)
>   # define DP_DSC_24_PER_DP_DSC_SINK          (1 << 2)
>   
> -#define DP_DSC_MAX_BPP_DELTA		    0x06E
> +#define DP_DSC_MAX_BPP_DELTA_VERSION_1		0x06E
>   # define DP_DSC_RGB_YCbCr444_MAX_BPP_DELTA_MASK 0x1f
>   # define DP_DSC_RGB_YCbCr420_MAX_BPP_DELTA_MASK 0xe0
> -
> -#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
> -# define DP_DSC_BITS_PER_PIXEL_1_2          0x3
> -# define DP_DSC_BITS_PER_PIXEL_1_1          0x4
> -# define DP_DSC_BITS_PER_PIXEL_MASK         0x7
> +# define DP_DSC_BPP_DELTA_444			16
> +# define DP_DSC_BPP_DELTA_420			12
> +# define DP_DSC_BPP_DELTA_SHIFT_420		5
> +
> +#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
> +# define DP_DSC_BITS_PER_PIXEL_1_2		0x3
> +# define DP_DSC_BITS_PER_PIXEL_1_1		0x4
> +# define DP_DSC_BITS_PER_PIXEL_MASK		0x7
> +# define DP_DSC_NATIVE4222_MAX_BPP_DELTA_MASK	0x78

This should be: _NATIVE_YCbCr422_ to match with existing code, and in 
line with the comments on the previous patch.


Regards,

Ankit

> +# define DP_DSC_BPP_DELTA_NATIVE_422		16
>   
>   #define DP_PSR_SUPPORT                      0x070   /* XXX 1.2? */
>   # define DP_PSR_IS_SUPPORTED                1