Re: [PATCH 4/5] usb: typec: mux: ps883x: add a delay after writing config regs

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

Hi,

On Sat, Jul 18, 2026 at 07:06:32PM +0200, Jens Glathe via B4 Relay wrote:
> From: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
> 
> The config regs seem to need a few ms to propagate the changes through the
> system (like, PLLs). This improves the hotplug dp altmode success rate
> on the Lenovo 40B0 dock to 100%.

20ms - 30ms is a bit more than a few ms.

> Tested with T14s G6 and 40B0 dock on the HDMI port with a type-c host cable.
> 
> Assisted-by: Gemini:3
> Signed-off-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
> ---
>  drivers/usb/typec/mux/ps883x.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/usb/typec/mux/ps883x.c b/drivers/usb/typec/mux/ps883x.c
> index 3533d4f363286..3ca2952e6a0a3 100644
> --- a/drivers/usb/typec/mux/ps883x.c
> +++ b/drivers/usb/typec/mux/ps883x.c
> @@ -185,6 +185,8 @@ static int ps883x_configure(struct ps883x_retimer *retimer, int cfg0,
>  		return ret;
>  	}
>  
> +	usleep_range(20000, 30000);

/* <explanation why is the delay is necessary> */
fsleep(20000);

>  	return 0;
>  }

thanks,

-- 
heikki