Re: [PATCH v6 4/4] leds: trigger: implement a tty trigger

[Johan Hovold]

On Wed, Feb 19, 2020 at 12:19:13PM +0100, Johan Hovold wrote:
> On Wed, Feb 19, 2020 at 12:03:06PM +0100, Uwe Kleine-König wrote:
> > On Wed, Feb 19, 2020 at 11:52:39AM +0100, Johan Hovold wrote:

> > If I understand correctly calling tty_kopen_shared() doesn't open the
> > device, just keep it referenced which prevents it to disappear. Unless I
> > miss something it doesn't result in the tty's .open() being called.
> 
> So tty_kopen_shared() is something you added. Judging from a quick look
> it seems you can only attach a trigger to an already open port, but the
> trigger will then keep the port open (again, consider modem control,
> power).

Sorry, my bad; this reference shouldn't prevent the port from being
closed.

The fact that you need the port to be open before you can attach a
trigger does sound like a problem though (e.g. consider udev rules).

Johan