[PATCH v1] usb: typec: ucsi: Pass full DP config payload in SET_NEW_CAM for DP alt mode

[PATCH v1] usb: typec: ucsi: Pass full DP config payload in SET_NEW_CAM for DP alt mode

[madhu.m]

From: Madhu M <madhu.m@intel.com>

In the UCSI Specification Revision 3.1 RC1, bits 32-63 of the SET_NEW_CAM
command hold the 32-bit Alternate Mode Specific (AMSpecific) field.

For DisplayPort Alternate Mode, this field must contain the full
32-bit DisplayPort configuration VDO payload that the OPM wants the
connector to operate in, rather than just the pin assignment value.
This AMSpecific value follows the DisplayPort Configurations defined
in the DisplayPort Alt Mode on USB Type-C Specification v2.1a,
Table 5-13: SOP DisplayPort Configurations.

Signed-off-by: Madhu M <madhu.m@intel.com>
Reviewed-by: Jameson Thies <jthies@google.com>
Reviewed-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/typec/ucsi/displayport.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
index 67a0991a7b76..2e3d7c734d9f 100644
--- a/drivers/usb/typec/ucsi/displayport.c
+++ b/drivers/usb/typec/ucsi/displayport.c
@@ -185,13 +185,12 @@ static int ucsi_displayport_status_update(struct ucsi_dp *dp)
 
 static int ucsi_displayport_configure(struct ucsi_dp *dp)
 {
-	u32 pins = DP_CONF_GET_PIN_ASSIGN(dp->data.conf);
 	u64 command;
 
 	if (!dp->override)
 		return 0;
 
-	command = UCSI_CMD_SET_NEW_CAM(dp->con->num, 1, dp->offset, pins);
+	command = UCSI_CMD_SET_NEW_CAM(dp->con->num, 1, dp->offset, dp->data.conf);
 
 	return ucsi_send_command(dp->con->ucsi, command, NULL, 0);
 }
-- 
2.34.1

Re: [PATCH v1] usb: typec: ucsi: Pass full DP config payload in SET_NEW_CAM for DP alt mode

[Greg KH]

On Fri, Jun 19, 2026 at 08:33:29PM +0530, madhu.m@intel.com wrote:
> From: Madhu M <madhu.m@intel.com>
> 
> In the UCSI Specification Revision 3.1 RC1, bits 32-63 of the SET_NEW_CAM
> command hold the 32-bit Alternate Mode Specific (AMSpecific) field.
> 
> For DisplayPort Alternate Mode, this field must contain the full
> 32-bit DisplayPort configuration VDO payload that the OPM wants the
> connector to operate in, rather than just the pin assignment value.
> This AMSpecific value follows the DisplayPort Configurations defined
> in the DisplayPort Alt Mode on USB Type-C Specification v2.1a,
> Table 5-13: SOP DisplayPort Configurations.
> 
> Signed-off-by: Madhu M <madhu.m@intel.com>
> Reviewed-by: Jameson Thies <jthies@google.com>
> Reviewed-by: Andrei Kuchynski <akuchynski@chromium.org>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/usb/typec/ucsi/displayport.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
> index 67a0991a7b76..2e3d7c734d9f 100644
> --- a/drivers/usb/typec/ucsi/displayport.c
> +++ b/drivers/usb/typec/ucsi/displayport.c
> @@ -185,13 +185,12 @@ static int ucsi_displayport_status_update(struct ucsi_dp *dp)
>  
>  static int ucsi_displayport_configure(struct ucsi_dp *dp)
>  {
> -	u32 pins = DP_CONF_GET_PIN_ASSIGN(dp->data.conf);
>  	u64 command;
>  
>  	if (!dp->override)
>  		return 0;
>  
> -	command = UCSI_CMD_SET_NEW_CAM(dp->con->num, 1, dp->offset, pins);
> +	command = UCSI_CMD_SET_NEW_CAM(dp->con->num, 1, dp->offset, dp->data.conf);
>  
>  	return ucsi_send_command(dp->con->ucsi, command, NULL, 0);
>  }
> -- 
> 2.34.1
> 
> 

SHouldn't this have a Fixes: and cc: stable tag?

thanks,

greg k-h

RE: [PATCH v1] usb: typec: ucsi: Pass full DP config payload in SET_NEW_CAM for DP alt mode

[M, Madhu]

You're right, it should. The bug was introduced in af8622f6a585, which has
been around since v5.2, so I'll add:

Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
Cc: stable@vger.kernel.org

I'll send a v2 with these tags added.

Thanks,
Madhu M

-----Original Message-----
From: Greg KH <gregkh@linuxfoundation.org> 
Sent: 19 June 2026 20:10
To: M, Madhu <madhu.m@intel.com>
Cc: heikki.krogerus@linux.intel.com; Katiyar, Pooja <pooja.katiyar@intel.com>; akuchynski@chromium.org; jthies@google.com; johan@kernel.org; linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] usb: typec: ucsi: Pass full DP config payload in SET_NEW_CAM for DP alt mode

On Fri, Jun 19, 2026 at 08:33:29PM +0530, madhu.m@intel.com wrote:
> From: Madhu M <madhu.m@intel.com>
> 
> In the UCSI Specification Revision 3.1 RC1, bits 32-63 of the 
> SET_NEW_CAM command hold the 32-bit Alternate Mode Specific (AMSpecific) field.
> 
> For DisplayPort Alternate Mode, this field must contain the full 
> 32-bit DisplayPort configuration VDO payload that the OPM wants the 
> connector to operate in, rather than just the pin assignment value.
> This AMSpecific value follows the DisplayPort Configurations defined 
> in the DisplayPort Alt Mode on USB Type-C Specification v2.1a, Table 
> 5-13: SOP DisplayPort Configurations.
> 
> Signed-off-by: Madhu M <madhu.m@intel.com>
> Reviewed-by: Jameson Thies <jthies@google.com>
> Reviewed-by: Andrei Kuchynski <akuchynski@chromium.org>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/usb/typec/ucsi/displayport.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/displayport.c 
> b/drivers/usb/typec/ucsi/displayport.c
> index 67a0991a7b76..2e3d7c734d9f 100644
> --- a/drivers/usb/typec/ucsi/displayport.c
> +++ b/drivers/usb/typec/ucsi/displayport.c
> @@ -185,13 +185,12 @@ static int ucsi_displayport_status_update(struct 
> ucsi_dp *dp)
>  
>  static int ucsi_displayport_configure(struct ucsi_dp *dp)  {
> -	u32 pins = DP_CONF_GET_PIN_ASSIGN(dp->data.conf);
>  	u64 command;
>  
>  	if (!dp->override)
>  		return 0;
>  
> -	command = UCSI_CMD_SET_NEW_CAM(dp->con->num, 1, dp->offset, pins);
> +	command = UCSI_CMD_SET_NEW_CAM(dp->con->num, 1, dp->offset, 
> +dp->data.conf);
>  
>  	return ucsi_send_command(dp->con->ucsi, command, NULL, 0);  }
> --
> 2.34.1
> 
> 

SHouldn't this have a Fixes: and cc: stable tag?

thanks,

greg k-h