[PATCH v4 14/14] tty: gunyah: Add tty console driver for RM Console Services

Greg Kroah-Hartman gregkh at linuxfoundation.org
Fri Oct 7 00:40:52 PDT 2022


On Thu, Oct 06, 2022 at 10:59:51PM -0700, Elliot Berman wrote:
> > > + */
> > > +#define RSC_MGR_TTY_ADAPTERS		16
> > 
> > We can have dynamic tty devices, so I don't understand this comment.
> > What really is the problem here?
> > 
> 
> Yes, I see the confusion. Dynamic device addition of tty devices is
> supported. As I understand, you need to know the maximum number of lines
> that could be added, and that is limitation I was referring to.

What do you mean by "lines"?  That's not a tty kernel term.

> Is this comment better?
> 
> The Linux TTY code requires us to know ahead of time how many lines we
> might need. Each line here corresponds to a VM. 16 seems like a
> reasonable number of lines for systems that are running Gunyah and using
> the provided console interface.

Again, line?  Do you mean port?

> > > +	cons_data->tty_driver->driver_name = "gh";

KBUILD_MODNAME?

> > > +	cons_data->tty_driver->name = "ttyGH";
> > 
> > Where did you pick this name from?
> > 
> > Where is it documented?
> > 
> 
> "GH" is the shorthand we've been using for "Gunyah". I didn't find
> documentation for dynamically assigned char devices, but if it exists, I can
> add entry for ttyGH.

Why use a new name at all?  Why not stick with the existing tty names
and device numbers?

thanks,

greg k-h



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