Re: [gentoo-user] Soft scrolling on framebuffer consoles - New version of the patch - with GPM handling.

[Alan Mackenzie]

Hello, Peter.

On Sun, Jan 01, 2023 at 15:13:02 +0000, Alan Mackenzie wrote:
> On Sat, Dec 31, 2022 at 16:13:23 +0000, Alan Mackenzie wrote:
> > On Sat, Dec 31, 2022 at 15:47:01 +0000, Peter Humphrey wrote:
> > > Hello Alan,
> > > On Saturday, 31 December 2022 14:08:43 GMT you wrote:

> [ .... ]

> > > I think you've put your finger on it:

> > > $ file /lib/rc/console/font
> > > /lib/rc/console/font: Linux/i386 PC Screen Font v2 data, 256 characters,
> > > Unicode directory, 22x11

> > > I use consolefont="ter-122n" from the terminus-font package. It's a long time
> > > since I was able to read a high-resolution screen in its native resolution.

> That's a nice font.  I could get used to it if I wasn't so attached to
> the 8x16 font.

[ .... ]

> The included patch is still imperfect.  When booting in 11x22, it doesn't
> handle the early boot messages at all well.  Also, I'm a little confused
> by what a low-level scroll function is meant to do - sometimes, scrolling
> happens when you type a CR, and want a line on the screen to be space
> filled.  Other times, you type <shift><PgUp> and don't want any space
> filling to happen.  So I'm not convinced that scrolling, invoked by, say,
> an editor program, will work correctly.

OK, I'm now including a revised patch which is less imperfect.  ;-)

To use it, please apply it to the vanilla gentoo-sources 5.15.88 (or
similar) with the usual:

    patch -p1 < 5.15.80-GPM.20230126.diff

, followed by configuring in CONFIG_FRAMEBUFFER_CONSOLE_SOFT_SCROLLBACK
and CONFIG_FRAMEBUFFER_CONSOLE_SOFT_SCROLLBACK_GPM, and setting an
appropriate scrollback buffer size as already done.  The ..._GPM is new,
but is enabled by default.  Build and install the kernel, then reboot
into it, to try it out.

I think it will work better than the previous patch.

> >>>> To use it, please apply the supplied patch ON TOP OF the patch I
> >>>> posted here on 12th December.  Proceed as documented in that post,
> >>>> up until configuring the kernel - in Device drivers/Graphic
> >>>> support/Console display driver support, there's an extra item
> >>>> "Enable a working GPM for scrolled back scrollback buffer in System
> >>>> RAM" which should be enabled by default.  Check this is set up
> >>>> properly.  Then build and install the kernel.  Then reboot into it
> >>>> and try it out.

Again, on any problems please let me know and I'll try to fix them.  As
ever, there are no guarantees, etc., etc., etc.  My only promise is that
there's no malicious code in the patch.

> > > --
> > > Regards,
> > > Peter.

-- 
Alan Mackenzie (Nuremberg, Germany).