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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon, 14 Sep 2020 18:28:34 -0700
Message-ID: <CAHk-=wiNTWpqUF0HgzoyPGEaaAjxD-Bor+EE3DbJ52S30cfCWg@mail.gmail.com>
Subject: Re: fbcon: remove soft scrollback code (missing Doc. patch)
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Yuan Ming <yuanmingbuaa@gmail.com>, Willy Tarreau <w@1wt.eu>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        NopNop Nop <nopitydays@gmail.com>,
        =?UTF-8?B?5byg5LqR5rW3?= <zhangyunhai@nsfocus.com>,
        Andy Lutomirski <luto@amacapital.net>
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On Mon, Sep 14, 2020 at 6:19 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> Now someone can remove the documentation for scrollback (and "no-scroll")...

Note that scrollback hasn't actually gone away entirely - the original
scrollback supported by _hardware_ still exists.

Of course, that's really just the old-fashioned text VGA console, but
that one actually scrolls not by moving any bytes around, but by
moving the screen start address. And the scrollback similarly isn't
about any software buffering, but about the ability of moving back
that screen start address.

Do people use that? Probably not. But it wasn't removed because it
didn't have any of the complexities and bitrot that all the software
buffering code had.

That said, I didn't check how much of the documentation is for the VGA
text console, and how much of it is for the actual software scrollback
for fbcon etc. So it is entirely possible that all the docs are about
the removed parts.

              Linus