linux-kernel - Re: [PATCH 0/6] vt: no blinking on console, 256/24-bit color improvements

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Message-ID: <CAMuHMdVPx40SL2kqv+nRUDoX0GL4uKoZd7gYmab94T2RyrpkMw@mail.gmail.com>
Date:   Mon, 23 Jul 2018 13:07:27 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Adam Borowski <kilobyte@...band.pl>
Cc:     Greg KH <gregkh@...uxfoundation.org>, Jiri Slaby <jslaby@...e.com>,
        linux-console@...r.kernel.org,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/6] vt: no blinking on console, 256/24-bit color improvements

Hi Adam,

On Mon, Jul 23, 2018 at 12:42 PM Adam Borowski <kilobyte@...band.pl> wrote:
> On Mon, Jul 23, 2018 at 10:53:29AM +0200, Geert Uytterhoeven wrote:
> > On Sat, Jul 21, 2018 at 11:39 PM Adam Borowski <kilobyte@...band.pl> wrote:
> > > Technically, every console can be made to blink by drawing/clearing affected
> > > characters a few times per second, but that'd be quite a waste of coding
> > > time and kernel size.  There's a reason browsers dropped support for <blink>
> > > and text-decoration:blink.
> >
> > It's very simple and fast to implement in fbcon for FB_TYPE_PLANES or
> > FB_TYPE_INTERLEAVED_PLANES and FB_VISUAL_PSEUDOCOLOR ;-)
>
> Interesting...  I'm still not going to do the effort to implement that
> (which would require learning fbdev internals first), though.  But while I
> dislike this feature, someone else might want it.
>
> The main problem here is that there are only 8 or 7 bits available for
> attributes, thus it's better to use them for something more useful.  And
> here, fbcon already interprets this bit as bright background, thus this
> patchset makes vt use it instead of non-existant blink.

Even better that they are mutually exclusive ;-)  So it can work fine with
only 4 bitplanes.

That means bitplane 3 means either bright background (palette[8..15] are
the extra-bright versions of palette[0..7]) or blinking (palette[8..15]
alternate between palette[0..7] and all zeroes).

> There'll be more bits available once attributes get migrated into uniscr --
> either 11 or 32 bits depending on chosen implementation.  But I still
> wouldn't go too wild with them: the console is meant for recovery tasks as
> on any properly working system you can have an X terminal configured for
> pixel-to-pixel identical behaviour as anything console can do.  Thus, only
> cheap improvements to attributes make sense.  This patchset is currently at
> +3 net lines, this certainly counts as cheap.

Assumed all those systems are sufficiently powerful to still run X
(said the guy who once ran X with mem=2M on his Amiga, just to prove it could
 work ;-)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds