On Sun, Feb 09, 2025 at 03:19:26PM +0800, joswang wrote:
> From: Jos Wang <joswang@xxxxxxxxxx>
>
> Although some Type-C DRD devices that do not support the DP Sink
> function (such as Huawei Mate 40Pro), the Source Port initiates
> Enter Mode CMD, but the device responds to Enter Mode ACK, the
> Source port then initiates DP Status Update CMD, and the device
> responds to DP Status Update NAK.
>
> As PD2.0 spec ("6.4.4.3.4 Enter Mode Command")，A DR_Swap Message
> Shall Not be sent during Modal Operation between the Port Partners.
> At this time, the source port initiates DR_Swap message through the
> "echo device > /sys/class/typec/port0/data_role" command to switch
> the data role from host to device. The device will initiate a Hard
> Reset for recovery, resulting in the failure of data role swap.
>
> Therefore, when DP Status Update NAK is received, Exit Mode CMD is
> initiated to exit the currently entered DP altmode.
>
> Signed-off-by: Jos Wang <joswang@xxxxxxxxxx>
This looks okay to me, but Benson, can you take a look at this?
> ---
> drivers/usb/typec/altmodes/displayport.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index ac84a6d64c2f..b09b58d7311d 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -393,6 +393,10 @@ static int dp_altmode_vdm(struct typec_altmode *alt,
> break;
> case CMDT_RSP_NAK:
> switch (cmd) {
> + case DP_CMD_STATUS_UPDATE:
> + if (typec_altmode_exit(alt))
> + dev_err(&dp->alt->dev, "Exit Mode Failed!\n");
> + break;
> case DP_CMD_CONFIGURE:
> dp->data.conf = 0;
> ret = dp_altmode_configured(dp);
> --
> 2.17.1
--
heikki
