Re: [PATCH] usb: typec: tipd: Fix Thunderbolt altmode VDOs for cd321x

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Thu, Aug 13, 2026 at 08:16:15PM +0200, Sven Peter wrote:
> The Intel VID status register is actually 9 bytes long and doesn't
> contain the raw VDOs but only the upper 16bits for device mode and enter
> mode. Shift those two fields into place and reconstruct the cable
> discover mode VDO from the data status register instead since it's not
> directly accessible. With this fixed now the correct VDOs are forwarded
> to the PHY and the to-be-submitted Thunderbolt/USB4 native host interface
> so that the right mode can be negotiated and the link actually comes up.
> 
> Link: https://www.ti.com/lit/ug/slvubh2b/slvubh2b.pdf
> Fixes: 0b31c978935f ("usb: typec: tipd: Read USB4, Thunderbolt and DisplayPort status for cd321x")
> Fixes: 82432bbfb9e8 ("usb: typec: tipd: Handle mode transitions for CD321x")
> Cc: stable@vger.kernel.org
> Signed-off-by: Sven Peter <sven@kernel.org>

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/usb/typec/tipd/core.c     | 17 +++++++++++++----
>  drivers/usb/typec/tipd/tps6598x.h |  4 ++--
>  2 files changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
> index d5ee0af9058b..159d1a2f9a1f 100644
> --- a/drivers/usb/typec/tipd/core.c
> +++ b/drivers/usb/typec/tipd/core.c
> @@ -114,7 +114,6 @@ struct tps6598x_intel_vid_status_reg {
>  	__le32 attention_vdo;
>  	__le16 enter_vdo;
>  	__le16 device_mode;
> -	__le16 cable_mode;
>  } __packed;
>  
>  /* Standard Task return codes */
> @@ -700,9 +699,19 @@ static void cd321x_typec_update_mode(struct tps6598x *tps, struct cd321x_status
>  		   cd321x->state.mode == TYPEC_TBT_MODE)
>  			return;
>  
> -		tbt_data.cable_mode = le16_to_cpu(st->intel_vid_status.cable_mode);
> -		tbt_data.device_mode = le16_to_cpu(st->intel_vid_status.device_mode);
> -		tbt_data.enter_vdo = le16_to_cpu(st->intel_vid_status.enter_vdo);
> +		tbt_data.cable_mode = TBT_MODE |
> +			TBT_SET_CABLE_SPEED(TPS_DATA_STATUS_TBT_CABLE_SPEED(st->data_status)) |
> +			TBT_SET_CABLE_ROUNDED(TPS_DATA_STATUS_TBT_CABLE_GEN(st->data_status));
> +		if (st->data_status & TPS_DATA_STATUS_OPTICAL_CABLE)
> +			tbt_data.cable_mode |= TBT_CABLE_OPTICAL;
> +		if (st->data_status & TPS_DATA_STATUS_ACTIVE_LINK_TRAIN)
> +			tbt_data.cable_mode |= TBT_CABLE_LINK_TRAINING;
> +		if (st->data_status & TPS_DATA_STATUS_ACTIVE_CABLE)
> +			tbt_data.cable_mode |= TBT_CABLE_ACTIVE_PASSIVE;
> +		tbt_data.device_mode = TBT_MODE |
> +			(u32)le16_to_cpu(st->intel_vid_status.device_mode) << 16;
> +		tbt_data.enter_vdo =
> +			(u32)le16_to_cpu(st->intel_vid_status.enter_vdo) << 16;
>  		cd321x->state.alt = cd321x->port_altmode_tbt;
>  		cd321x->state.mode = TYPEC_TBT_MODE;
>  		cd321x->state.data = &tbt_data;
> diff --git a/drivers/usb/typec/tipd/tps6598x.h b/drivers/usb/typec/tipd/tps6598x.h
> index 03edbb77bbd6..d172c84ada74 100644
> --- a/drivers/usb/typec/tipd/tps6598x.h
> +++ b/drivers/usb/typec/tipd/tps6598x.h
> @@ -206,10 +206,10 @@
>  #define TPS_DATA_STATUS_DP_PIN_ASSIGNMENT(x) \
>  	TPS_FIELD_GET(TPS_DATA_STATUS_DP_PIN_ASSIGNMENT_MASK, (x))
>  #define TPS_DATA_STATUS_TBT_CABLE_SPEED_MASK   GENMASK(27, 25)
> -#define TPS_DATA_STATUS_TBT_CABLE_SPEED \
> +#define TPS_DATA_STATUS_TBT_CABLE_SPEED(x) \
>  	TPS_FIELD_GET(TPS_DATA_STATUS_TBT_CABLE_SPEED_MASK, (x))
>  #define TPS_DATA_STATUS_TBT_CABLE_GEN_MASK     GENMASK(29, 28)
> -#define TPS_DATA_STATUS_TBT_CABLE_GEN \
> +#define TPS_DATA_STATUS_TBT_CABLE_GEN(x) \
>  	TPS_FIELD_GET(TPS_DATA_STATUS_TBT_CABLE_GEN_MASK, (x))
>  
>  /* Map data status to DP spec assignments */
> 
> ---
> base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
> change-id: 20260813-b4-tipd-vdo-fix-44e65b48aea3
> 
> Best regards,
> --  
> Sven Peter <sven@kernel.org>
> 

-- 
heikki