Re: [PATCH v5 1/3] drm/i915/vbt: Add eDP Data rate overrride field in VBT

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

On 8/19/2025 1:36 PM, Suraj Kandpal wrote:
> Add edp_data_rate_override field VBT which gives us a mask
> of rates which needs to be skipped in favour of
> subsequent higher rate.
>
> --v2
> -Rename vbt field [Jani]
> -Fix comment to 263+ [Jani]
> -Use BIT_U32 [Jani]
> -Fix the bits assignment in vbt [Jani]
>
> Bspec: 20124
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>


> ---
>   drivers/gpu/drm/i915/display/intel_bios.c     |  4 +++-
>   drivers/gpu/drm/i915/display/intel_vbt_defs.h | 17 +++++++++++++++++
>   2 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 9c268bed091d..8337ebe0f2c8 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -2747,8 +2747,10 @@ static int child_device_expected_size(u16 version)
>   {
>   	BUILD_BUG_ON(sizeof(struct child_device_config) < 40);
>   
> -	if (version > 256)
> +	if (version > 263)
>   		return -ENOENT;
> +	else if (version >= 263)
> +		return 44;
>   	else if (version >= 256)
>   		return 40;
>   	else if (version >= 216)
> diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> index 92c04811aa28..d4d89d5573db 100644
> --- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> +++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> @@ -437,6 +437,21 @@ enum vbt_gmbus_ddi {
>   #define BDB_230_VBT_DP_MAX_LINK_RATE_UHBR13P5	6
>   #define BDB_230_VBT_DP_MAX_LINK_RATE_UHBR20	7
>   
> +/* EDP link rate 263+ */
> +#define BDB_263_VBT_EDP_LINK_RATE_1_62		BIT_U32(0)
> +#define BDB_263_VBT_EDP_LINK_RATE_2_16		BIT_U32(1)
> +#define BDB_263_VBT_EDP_LINK_RATE_2_43		BIT_U32(2)
> +#define BDB_263_VBT_EDP_LINK_RATE_2_7		BIT_U32(3)
> +#define BDB_263_VBT_EDP_LINK_RATE_3_24		BIT_U32(4)
> +#define BDB_263_VBT_EDP_LINK_RATE_4_32		BIT_U32(5)
> +#define BDB_263_VBT_EDP_LINK_RATE_5_4		BIT_U32(6)
> +#define BDB_263_VBT_EDP_LINK_RATE_6_75		BIT_U32(7)
> +#define BDB_263_VBT_EDP_LINK_RATE_8_1		BIT_U32(8)
> +#define BDB_263_VBT_EDP_LINK_RATE_10		BIT_U32(9)
> +#define BDB_263_VBT_EDP_LINK_RATE_13_5		BIT_U32(10)
> +#define BDB_263_VBT_EDP_LINK_RATE_20		BIT_U32(11)
> +#define BDB_263_VBT_EDP_NUM_RATES		12
> +
>   /*
>    * The child device config, aka the display device data structure, provides a
>    * description of a port and its configuration on the platform.
> @@ -547,6 +562,8 @@ struct child_device_config {
>   	u8 dp_max_link_rate:3;					/* 216+ */
>   	u8 dp_max_link_rate_reserved:5;				/* 216+ */
>   	u8 efp_index;						/* 256+ */
> +	u32 edp_data_rate_override:12;				/* 263+ */
> +	u32 edp_data_rate_override_reserved:20;			/* 263+ */
>   } __packed;
>   
>   struct bdb_general_definitions {