Re: [PATCH] USB: serial: Support attaching serdev devices

[Johan Hovold <johan@kernel.org>]

On Thu, Sep 17, 2026 at 05:21:52PM +0200, Alban Bedel wrote:
> On Thu, 17 Sep 2026 15:08:11 +0100
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> > Please read the archives for why we don't want to do this unless/until
> > serdev is "fixed" to properly handle dynamic device removals.
> 
> All I could find is the "USB-Serial serdev support" thread from last
> year which sadly doesn't provides much details. Like Marco Felsch back
> then I tested disabling/enabling the USB port and didn't have any
> issue, the serdev device get removed and added back just fine. In my
> case the serdev driver provides an I2C bus, all devices on it get
> removed and added back again as well and work just fine.
> 
> I really fail to see an issue in pratice, would you care to explain
> what I'm missing here?

Serial drivers use hangups when tearing down their ports. Serdev does
not support that so the port is shut down underneath the serdev client
while still in use, which can lead to all sorts of issues.

Johan