2.6.8 Kernel: no console, but X working fine

[Frank O. Fackelmayer]

Hi all,
In my Debian-sarge installation (all up to date) I'm having a problem to
get a "normal" text console. After booting, I come to the Tux, but there
are no messages displayed below it. The system continues booting,
though, and after a short while Xfree comes up and I get a normal kdm
login window. I can do almost all thet I want in Konsole under KDE, but
there is no way to get to the text console: pressing the keys to switch
just leaves me with a blank black screen.

My hardware: Powermac 7300 with Sonnet G3. Booted via BootX into kernel
2.6.8 (the debian package, no home-brew) with "no video driver"
(video=ofonly) checked. It did/does work flawlessly under Kernel 2.2.20
when I use this one for booting.
(BTW: Is Kernel 2.6.8 a significant improvement over 2.2.20 on this old
machine? I could stick with the old Kernel which works fine, but I'd
love to be up-to-date...)

Does anyone know what's wrong? Does anybody have the same problem on
similar hardware? From what I read I think it is a framebuffer problem
in the new Kernel. Is there anything (simple) I can try? I will also try
compiling my own Kernel when necessary, but I'll need advice how to get
the console running then (settings in .config).

Thanks in advance,
Frank

[Thomas Jahns]

Post by Frank O. Fackelmayer
In my Debian-sarge installation (all up to date) I'm having a problem
to get a "normal" text console. After booting, I come to the Tux, but
there are no messages displayed below it. The system continues
booting, though, and after a short while Xfree comes up and I get a
normal kdm login window. I can do almost all thet I want in Konsole
under KDE, but there is no way to get to the text console: pressing
the keys to switch just leaves me with a blank black screen.
My hardware: Powermac 7300 with Sonnet G3. Booted via BootX into
kernel 2.6.8 (the debian package, no home-brew) with "no video driver"
(video=ofonly) checked. It did/does work flawlessly under Kernel
2.2.20 when I use this one for booting.
(BTW: Is Kernel 2.6.8 a significant improvement over 2.2.20 on this
old machine? I could stick with the old Kernel which works fine, but
I'd love to be up-to-date...)
Does anyone know what's wrong? Does anybody have the same problem on
similar hardware? From what I read I think it is a framebuffer problem
in the new Kernel. Is there anything (simple) I can try? I will also
try compiling my own Kernel when necessary, but I'll need advice how
to get the console running then (settings in .config).

Unfortunately support for PowerMac framebuffers has become less and less
reliable after about 2.4.22. But newer kernels are only needed if you
want to have newer features like XFS support.

I think there is a PowerMac ppc kernel on the debian site from the 2.4.x
age that might work better for you.

Are you using the built-in framebuffer of the 7300 or a PCI graphics
adapter?

Thomas Jahns

[Frank O. Fackelmayer]

Post by Thomas Jahns
Unfortunately support for PowerMac framebuffers has become less and less
reliable after about 2.4.22.

is that a general problem of the newer kernels, or a Debian-specific
one? If it is Debian-specific, recompiling the kernel with tweaked
configs could help. Otherwise changes to the source code would be
necessary, for which I unfortunately have neither enough time nor knowledge.

Post by Thomas Jahns
But newer kernels are only needed if you
want to have newer features like XFS support.

I see. It is quite hard for someone new in the Linux field to see what
has changed between different kernels. Changelogs are ok to see the
details, but I yet have to find a nice overview. Not a list of bugfixes,
but real changes to functionality, new features etc.

Post by Thomas Jahns
I think there is a PowerMac ppc kernel on the debian site from the 2.4.x
age that might work better for you.

I can try that one, of course.

Post by Thomas Jahns
Are you using the built-in framebuffer of the 7300 or a PCI graphics
adapter?

I tried both, with identical negative result.

greetings,
Frank

[Thomas Jahns]

Post by Frank O. Fackelmayer

Post by Thomas Jahns
Unfortunately support for PowerMac framebuffers has become less and
less reliable after about 2.4.22.

is that a general problem of the newer kernels, or a Debian-specific
one? If it is Debian-specific, recompiling the kernel with tweaked
configs could help. Otherwise changes to the source code would be
necessary, for which I unfortunately have neither enough time nor knowledge.

No neither Debian- nor PPC-specific. The complete framebuffer driver
architecture has changed from 2.4.x to 2.6.x and drivers for cards that
are older and used rather infrequently today have not seen enough
attention to either upgrade at all (that's the case for e.g. the
Permedia 3 driver) or the changes made have not been checked thoroughly
on other platforms, that bit me for the atyfb driver, which was modified
around 2.4.23 in a way that only works on platforms similar to x86. If I
read the archives correctly, Benjamin Herrenschmidt (who maintains a
PPC-customized fork of the main kernel source) is currently trying to
solve that or has even already done so.

Post by Frank O. Fackelmayer

Post by Thomas Jahns
But newer kernels are only needed if you
want to have newer features like XFS support.

I see. It is quite hard for someone new in the Linux field to see what
has changed between different kernels. Changelogs are ok to see the
details, but I yet have to find a nice overview. Not a list of
bugfixes, but real changes to functionality, new features etc.

Yes, once you compile the new kernel regularly you become aware of the
more important changes. But 2.4.x kernel should be fine for most
purposes. ACPI, netfilter, device abstraction and driver consolidation
and kernel internals saw a number of improvements in 2.6.x but unless
you have a very recent piece of hardware or very high requirements for
interactivity/throughput etc. none of the changes is strictly needed.

Post by Frank O. Fackelmayer

Post by Thomas Jahns
Are you using the built-in framebuffer of the 7300 or a PCI graphics
adapter?

I tried both, with identical negative result.

:-(

Too bad. It seems to me it's not easy to get graphics (or rather
graphics and console) to work on these machines. As I mentioned I have
the same problems with internal framebuffer, an ATI Mach 64 and a Formac
Proformance III on a 7500.

Thomas Jahns

[Frank O. Fackelmayer]

I got myself an old Matrox Millennium PCI graphics card (for 1.99Euro from
ebay), which is better supported by Linux. Now I have the normal console and X
server running. It was necessary to switch off graphics acceleration in
XF86Config-4 to get the X server up, so it is a bit slow, but it's perfectly ok
for what I want to do.

Frank

[Frank O. Fackelmayer]

Post by Frank O. Fackelmayer
I got myself an old Matrox Millennium PCI graphics card (for 1.99Euro
from ebay), which is better supported by Linux. Now I have the normal
console and X server running. It was necessary to switch off graphics
acceleration in XF86Config-4 to get the X server up, so it is a bit
slow, but it's perfectly ok for what I want to do.

ok, I got acceleration to work. For others who might encounter a similar
problem, here is how. The documentation in
/usr/src/linux/Documentation/fb/matroxfb.txt tells that for acceleration and DRI
to work, "resolution and color depth of your X desktop must match resolution and
color depths of your virtual consoles, otherwise X will corrupt accelerator
settings". This was obviously the problem I had. Unfortunately, the matroxfb
driver for the kernel does not allow booting with any other resolution than
640x480 (VGA), irrespective of what parameters are passed from BootX (vesa-mode,
vmode, cmode...). So, resolution and color depth of the fb console must be
changed before the X server starts during the boot process. To this end, the
settings used in X can be set for the console by the fbset command; this is in
the fbset package in Debian that needs to be installed (apt-get install fbset).
In the next step, a simple script must be written to invoke the fbset command
during startup:

#!/bin/sh
echo "changing resolution ..."
/usr/sbin/fbset 1024x768-75
echo "... done"

and saved at the place where the bootup scripts are located. In my Debian case,
this is in /etc/rcS.d and I named the script S01chres so that it starts before
all other scripts. Of course the settings in the script must match your setting
in the Xserver configuration (for XFree86, this configuration is in
/etc/X11/XF86Config-4). Now, the resolution of the virtual console is changed
before the X server comes up, and acceleration is ok.

Frank

[pb]

Post by Frank O. Fackelmayer
Hi all,
In my Debian-sarge installation (all up to date) I'm having a problem to
get a "normal" text console. After booting, I come to the Tux, but there
are no messages displayed below it. The system continues booting, though,
and after a short while Xfree comes up and I get a normal kdm login
window. I can do almost all thet I want in Konsole under KDE, but there is
no way to get to the text console: pressing the keys to switch just leaves
me with a blank black screen.

I am having the exact same problem with YDL 3.0.1, on a beige G3 with ATI
Radeon 7000. Its really annoying. If I enable 'no video driver' then I do
get to see the console, but of course Xfree cannot start.

Is there anything I can do? eg. could I 'downgrade' kernel?