Re: [PATCH 17/16] Do not reset UTF8 on terminal reset

Antonino A. Daplas
2007-04-02T12:48:17Z

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On Mon, 2007-04-02 at 12:54 +0100, Paul LeoNerd Evans wrote:
> On Mon, Apr 02, 2007 at 07:44:13PM +0800, Antonino A. Daplas wrote:
> > > Is it OK to do that? I recall when I was originally looking at the code
> > > I didn't want to just remove that line, because it looked like that was
> > > being used to first initialise the vc* structure when it is created, as
> > > well as reset it every time. Doesn't this leave vc->vc_utf uninitialised
> > > when a new VC is allocated?
> >
> > That's true. We can move the line vc->vc_utf = 0; in vc_init()
> > instead.
>
> ...
>
> > @@ -2590,6 +2589,7 @@ static void vc_init(struct vc_data *vc,
> > vc->vc_rows = rows;
> > vc->vc_size_row = cols << 1;
> > vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
> > + vc->vc_utf = 0;
> >
> > set_origin(vc);
> > vc->vc_pos = vc->vc_origin;
>
> While we're on that subject, did you take a look at my original mail?

I did not actually.

> The intent with that patch was to allow system policy to state all new
> VCs are UTF-8-enabled by default. I feel that in 2007 this should be the
> default setting.
>
> Would it therefore be possible to have
>
> vc->vc_utf = some_default;
>
> where some_default comes maybe from a sysctl or some other configurable
> source? Or maybe even have a compiletime option?
>
> This would get around many bugs. For example, on boot, "unicode_start"
> can only set utf8 mode on the existing VCs 1 to 6. If X11 fails to
> start, debian nicely runs me the XKeepsCrashing program, which offers to
> show me logs and the like. It reads the locale, en_GB.UTF-8 and
> determines we're in UTF-8 mode, so outputs Unicode linedrawing
> characters for dialogs. Unfortunately, we're on VC7 which doesn't have
> UTF-8 mode turned on, so much mess results.
>
> It would be nice if the kernel's default UTF-8 mode for new VCs could be
> synched to whatever local policy was regarding locale.

How about this? This should allow us to reset the terminal without
affecting utf, and also allows setting of a global utf default that can
be set via boot option or sysfs:

echo 1 > /sys/module/vt/parameters/default_utf

Tony

>

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diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 1bbb45b..b9b3247 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -157,6 +157,8 @@ static void blank_screen_t(unsigned long
static void set_palette(struct vc_data *vc);

static int printable; /* Is console ready for printing? */
+static int default_utf;
+module_param(default_utf, int, S_IRUGO | S_IWUSR);

/*
* ignore_poke: don't unblank the screen when things are typed. This is
@@ -1497,7 +1499,6 @@ static void reset_terminal(struct vc_dat
vc->vc_charset = 0;
vc->vc_need_wrap = 0;
vc->vc_report_mouse = 0;
- vc->vc_utf = 0;
vc->vc_utf_count = 0;

vc->vc_disp_ctrl = 0;
@@ -2590,6 +2591,7 @@ static void vc_init(struct vc_data *vc,
vc->vc_rows = rows;
vc->vc_size_row = cols << 1;
vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
+ vc->vc_utf = default_utf;

set_origin(vc);
vc->vc_pos = vc->vc_origin;