[PATCH] usb: typec: tcpm: Fix VDM type for Enter Mode commands

[PATCH] usb: typec: tcpm: Fix VDM type for Enter Mode commands

[Andy Yan]

VDO() second parameter is VDM type (bit 15): 1 for SVDM, 0 for UVDM.
Using 'vdo ? 2 : 1' corrupts SVID low bit when vdo is non-NULL
(2 << 15 = BIT(16)). Enter Mode is always SVDM, hardcode to 1.

Fixes: 8face9aa57c8 ("usb: typec: Add parameter for the VDO to typec_altmode_enter()")
Signed-off-by: Andy Yan <andyshrk@163.com>
---

 drivers/usb/typec/tcpm/tcpm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 55fee96d3342a..3674e1cdde57b 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -3061,7 +3061,7 @@ static int tcpm_altmode_enter(struct typec_altmode *altmode, u32 *vdo)
 	if (svdm_version < 0)
 		return svdm_version;
 
-	header = VDO(altmode->svid, vdo ? 2 : 1, svdm_version, CMD_ENTER_MODE);
+	header = VDO(altmode->svid, 1, svdm_version, CMD_ENTER_MODE);
 	header |= VDO_OPOS(altmode->mode);
 
 	return tcpm_queue_vdm_unlocked(port, header, vdo, vdo ? 1 : 0, TCPC_TX_SOP);
@@ -3109,7 +3109,7 @@ static int tcpm_cable_altmode_enter(struct typec_altmode *altmode, enum typec_pl
 	if (svdm_version < 0)
 		return svdm_version;
 
-	header = VDO(altmode->svid, vdo ? 2 : 1, svdm_version, CMD_ENTER_MODE);
+	header = VDO(altmode->svid, 1, svdm_version, CMD_ENTER_MODE);
 	header |= VDO_OPOS(altmode->mode);
 
 	return tcpm_queue_vdm_unlocked(port, header, vdo, vdo ? 1 : 0, TCPC_TX_SOP_PRIME);
-- 
2.43.0

Re: [PATCH] usb: typec: tcpm: Fix VDM type for Enter Mode commands

[Heikki Krogerus]

On Thu, Jun 04, 2026 at 06:50:24PM +0800, Andy Yan wrote:
> VDO() second parameter is VDM type (bit 15): 1 for SVDM, 0 for UVDM.
> Using 'vdo ? 2 : 1' corrupts SVID low bit when vdo is non-NULL
> (2 << 15 = BIT(16)). Enter Mode is always SVDM, hardcode to 1.
> 
> Fixes: 8face9aa57c8 ("usb: typec: Add parameter for the VDO to typec_altmode_enter()")
> Signed-off-by: Andy Yan <andyshrk@163.com>

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

> ---
> 
>  drivers/usb/typec/tcpm/tcpm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 55fee96d3342a..3674e1cdde57b 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -3061,7 +3061,7 @@ static int tcpm_altmode_enter(struct typec_altmode *altmode, u32 *vdo)
>  	if (svdm_version < 0)
>  		return svdm_version;
>  
> -	header = VDO(altmode->svid, vdo ? 2 : 1, svdm_version, CMD_ENTER_MODE);
> +	header = VDO(altmode->svid, 1, svdm_version, CMD_ENTER_MODE);
>  	header |= VDO_OPOS(altmode->mode);
>  
>  	return tcpm_queue_vdm_unlocked(port, header, vdo, vdo ? 1 : 0, TCPC_TX_SOP);
> @@ -3109,7 +3109,7 @@ static int tcpm_cable_altmode_enter(struct typec_altmode *altmode, enum typec_pl
>  	if (svdm_version < 0)
>  		return svdm_version;
>  
> -	header = VDO(altmode->svid, vdo ? 2 : 1, svdm_version, CMD_ENTER_MODE);
> +	header = VDO(altmode->svid, 1, svdm_version, CMD_ENTER_MODE);
>  	header |= VDO_OPOS(altmode->mode);
>  
>  	return tcpm_queue_vdm_unlocked(port, header, vdo, vdo ? 1 : 0, TCPC_TX_SOP_PRIME);
> -- 
> 2.43.0

-- 
heikki