Re: [PATCH 3.13 35/99] tty: Set correct tty name in active sysfs attribute

[Peter Hurley]

On 02/22/2014 08:25 AM, David Herrmann wrote:
> Hi
>
> On Fri, Feb 21, 2014 at 11:53 PM, Ray Strode <halfline@xxxxxxxxx> wrote:
> > Hi,
> >
> > On Fri, Feb 21, 2014 at 11:01 AM, Kay Sievers <kay@xxxxxxxx> wrote:
> > > Why did the tty0 change to tty1 now? That doesn't look like a "driver
> > > name" vs. "device name" issue?
> >
> > I don't know if it's intentional, but the patch does:
> > +               int index = cs[i]->index;
> > ...
> > +               driver = cs[i]->device(cs[i], &index);
> >
> > which will presumably change the index from 0 to 1 because of this code:
> >
> > static struct tty_driver *vt_console_device(struct console *c, int *index)
> > {
> >         *index = c->index ? c->index-1 : fg_console;
> >         return console_driver;
> > }
> >
> > At least that's what it looks like is causing the problem from
> > browsing through the source a bit.
>
> Yepp, that's it. So if you configure the console to always be
> redirected to the foreground terminal, you simply bind it to tty0 and
> this file used to return tty0 then.
> With this patch, we actually return the foreground terminal instead,
> so tty0 is resolved to the real VT. This sounds like the correct
> behavior (even though it currently breaks poll() on this file). But if
> it breaks stuff, we should revert it and add a second file just like
> Peter suggested.

Or add sysfs entries for each console that exposes the device, so
that the underlying device is trivially discoverable, which is the
original problem.

Regards,
Peter Hurley

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