linux-kernel - Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems

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Message-ID: <20170403203204.2guyy63fkqwxpq4o@angband.pl>
Date:   Mon, 3 Apr 2017 22:32:04 +0200
From:   Adam Borowski <kilobyte@...band.pl>
To:     Nicolas Pitre <nicolas.pitre@...aro.org>
Cc:     Andi Kleen <andi@...stfloor.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        "linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for
 embedded systems

On Mon, Apr 03, 2017 at 04:09:38PM -0400, Nicolas Pitre wrote:
> On Mon, 3 Apr 2017, Adam Borowski wrote:
> 
> > On Mon, Apr 03, 2017 at 08:31:03AM -0700, Andi Kleen wrote:
> > > Except for that (and possibly VT) it is unlikely that people really
> > > rely on the obsolete terminal features from the 70ies. So it's a kind
> > > of cleanup.
> > 
> > But... but... but what shall we do without OLCUC?!?
> > 
> > I guess sending these features to the pasture would be nice even in
> > mainstream TTY.  Probably even without a Kconfig option to restore them.
> 
> Thing is... those arcane features don't take much code at all:
> 
> 		if (O_OLCUC(tty))
> 			c = toupper(c);
> 
> That's it. I didn't make the minitty code 5x smaller just by omitting 
> those.  ;-)

Except, those two lines have two bugs:
* it mangles most non-ASCII (kernel's toupper() hard-codes ISO-8859-1
  which no one uses anymore)
* it mangles a number of ANSI codes, making them unusable on any vt100ish
  terminal (ie, any post-1980)

I just happened to send an April Fools pull request
(https://github.com/kilobyte/linux.git runes) in which the first commit
fixes these:
https://github.com/kilobyte/linux/commit/268cde7c6dde54fcbc81df68d66b2389d77d01f2

Even though it's a real fix (unlike the subsequent fun), guess why I'm not
sending it to Greg and Jiri...

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