Re: [PATCH 1/1] USB: serial: option: add TDTECH MT5710-CN

[Johan Hovold <johan@kernel.org>]

On Tue, Jul 21, 2026 at 06:30:00PM +0800, Chukun Pan wrote:

> It is based on the Huawei HiSilicon Balong chip.

Thanks. I'll add that to commit message.

> > Do all interfaces need (and accept) the
> > USB_CDC_REQ_SET_CONTROL_LINE_STATE request sent on open
> > (unless suppressed with NCTRL())?
> 
> Sorry, I don't know. Is there any way to verify this?

There are some device that time out when sending that request on open()
and then you end up with a five second delay. That's likely not the case
here and we don't currently log any errors if the device just rejects
these calls.

If you have the time it would be interesting to know what that
usb_control_msg() in usb_wwan_send_setup() returns for each of the
ports. Just add a dev_info() in there and log it.

But either way, we already have other Huawei devices in the option
driver using similar configurations so I'll just go ahead and merge your
patch.

Johan