Re: [PATCH v2] s390/sclp_vt220: Fix console name to match device

From: Christian Borntraeger
Date: Wed Apr 28 2021 - 10:45:04 EST




On 28.04.21 15:38, Hendrik Brueckner wrote:
Hi Valentin,

I just had the chance to look into this console topic yesterday.

On Tue, Apr 27, 2021 at 09:40:10PM +0200, Valentin Vidic wrote:
Console name reported in /proc/consoles:

ttyS1 -W- (EC p ) 4:65

It is been a while ago when working on consoles. However, consoles are
typically devices without having a device node associated. There is special
handling for /dev/console wrt. to the preferred console in the tty layer.

A console device might be associated with a tty device but this is not a
requirement. For example, consider the net console that streams console
messages thru UDP and is not associated with a tty.

Because console and tty are different devices, names can also be different
which is, unfortunately, the case on s390.

another example is the ttyS0 console which is called sclp_line0 as a tty.
Doesnt the debian installer thus also fails when running in an LPAR?

It might still be a good idea to actually change the console name for the
ascii console as you patch does.

Therefore my suggestion here is not derive the tty device from the name
of the console, but rather looking at the associated tty being reported
as major minor number in /proc/console.

So yes we should definitely try to fix the installer program as well. All other
distros seem to handle this case fine.



does not match the char device name:

crw--w---- 1 root root 4, 65 May 17 12:18 /dev/ttysclp0

In the example above, 4:65 excactly ends up in /dev/ttysclp0.

I am also in contact with Christian and thanks to him to try this out
internally. At least, there are options to bring this forward and let's
figure out what the best solution will be.

Thanks and kind regards,
Hendrik

h