Re: [PATCH v2 02/10] usb: tcpm: continue polling after PD negotiation to handle source messages

Sebastian Reichel <[email protected]> Sat, 8 Aug 2026 23:35:02 +0200

Newsgroups	gmane.comp.boot-loaders.u-boot.general,gmane.comp.boot-loaders.u-boot
Message-ID	<aneg74rzS58HD1D1@venus>

Hi,

On Sun, Jun 21, 2026 at 10:06:38AM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <[email protected]>
> 
> After reaching SNK_READY or SRC_READY, the poll loop exits immediately.
> However, some PD sources send follow-up messages (e.g., Get_Sink_Cap,
> Get_Status) shortly after the explicit contract is established. Since
> the TCPCI hardware auto-sends GoodCRC for received messages, the
> source expects a timely response. If no response arrives within
> SenderResponseTimer (24-30ms), the source sends a Hard Reset,
> causing VBUS to drop and resetting VBUS-powered boards.
> 
> Add a 500ms settling period after reaching Ready state to process
> any follow-up messages from the source before entering low power
> mode and disabling PD message reception.
> 
> Signed-off-by: Peng Fan <[email protected]>
> ---

Reviewed-by: Sebastian Reichel <[email protected]>

Greetings,

-- Sebastian

>  drivers/usb/tcpm/tcpm.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/usb/tcpm/tcpm.c b/drivers/usb/tcpm/tcpm.c
> index 25ff0926cdf..d6af0fae7c1 100644
> --- a/drivers/usb/tcpm/tcpm.c
> +++ b/drivers/usb/tcpm/tcpm.c
> @@ -2252,6 +2252,16 @@ static void tcpm_poll_event(struct udevice *dev)
>  		tcpm_check_and_run_delayed_work(dev);
>  	}
>  
> +	if (port->state == SNK_READY || port->state == SRC_READY) {
> +		int settle;
> +
> +		for (settle = 0; settle < 1000; settle++) {
> +			drvops->poll_event(dev);
> +			udelay(500);
> +			tcpm_check_and_run_delayed_work(dev);
> +		}
> +	}
> +
>  	if (port->state != SNK_READY && port->state != SRC_READY)
>  		dev_warn(dev, "TCPM: exit in state %s\n",
>  			 tcpm_states[port->state]);
> 
> -- 
> 2.51.0
>

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