Date: Sat, 13 Sep 2014 21:42:12 +0100 From: Ben Morrow <ben@morrow.me.uk> To: dumbbell@FreeBSD.org, freebsd-stable@freebsd.org Subject: Re: 10.1 kernel device config for drm2 and kms drivers Message-ID: <20140913204209.GA18072@anubis.morrow.me.uk> In-Reply-To: <54146CCF.7020107@FreeBSD.org> References: <20140911064731.GA15930@rwpc15.gfn.riverwillow.net.au> <54115D2A.5020802@FreeBSD.org> <20140911084624.GK2737@kib.kiev.ua> <20140911211428.GA6247@anubis.morrow.me.uk>
next in thread | previous in thread | raw e-mail | index | archive | help
Quoth =?windows-1252?Q?Jean-S=E9bastien_P=E9dron?= <dumbbell@FreeBSD.org>:
> On 11.09.2014 23:14, Ben Morrow wrote:
> > I didn't realise it was possible to load radeonkms after boot.
> > Presumably if you do that you lose even more of the boot messages when
> > the new console loads? Currently it appears to lose everything that was
> > above the top of the screen when the new driver loaded; it would be
> > better (if possible) if it were to keep the scrollback as well.
>
> When a KMS driver is loaded, the history buffer of vt(4) grows and the
> current data is preserved. Therefore you should not lose any data.
>
> One caveat is that the cursor is put at the top of the screen, so the
> previous content is off-screen. Another issue is that the history size
> (hard-coded) is admittedly very small. But data should be there.
>
> Could you please describe your problem in more details?
Previously, with syscons, I could usually scroll back after boot had
finished and the login: prompt appeared and get all the way up to the
start of the kernel messages (the Copyright line).
Now, with vt, and loading radeonkms from rc.conf rather than
loader.conf, if I switch to the console, I can: scroll up through 8
screens of kernel and userland console messages until I come to a screen
which has
info: [drm] Initialised drm 1.1.0 20060810
in approximately the middle; then I can scroll up one more screen only,
which takes me to somewhere in the middle of probing the USB ports.
Looking at dmesg suggests there should be 3 or 4 more screens of
messages above that.
Obviously I can't be certain without trying more things that this isn't
just because the rest has gone off the top of the buffer, but ISTR when
I was first changing the machine over to vt that when I didn't load
radeonkms and stayed with vt_vga I could still scroll all the way up. I
may be misremembering, and/or making assumptions based on the fact the
end of the scrollback is about a screenful above drm loading; I can do
more experiments next time I reboot the machine if that would be
helpful.
Ben
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20140913204209.GA18072>