KN400: Blank / black screen when switching to text consoles

Created an attachment (id=3717)
My xorg.conf for Via KN400 Unichrome

Created an attachment (id=3718)
Output with lspci -v

Created an attachment (id=3719)
Xorg.0.log

Found the SOLUTION:

you have to add the following option in you xorg.conf:

Option "VBEModes" "true"

After enabling this option I'm able to use the "via" driver and get 3D and good speed!

You should add this as an option in your installer otherwise people like me with an Unichrome KM400 will have a "black screen of death".

Dapper Flight4:

The bug still exists. When GDM starts for the first time you get a "black screen of death" after installation finished.

There is no VBEModes option added automatically which on some graphic cards like in mine Acer notebook this will lead to a black screen.

I saw that you have unassigned this bug report.

To which package belongs this bug? Can you assign it to the right package? Or shall I post a new bug report for another package?

I wanted to test the Flight5 Live-CD but got again the black screen and could do nothing... I think that there are more users with VIA cards who could have the same problem.

It would be great if VIA users get a hint about this option in the installer so that they can add this option while installing Ubuntu. Haven't had a look if there is a hint in the boot screen in the live CD but it also would be great if you can insert a hint that people have to start it with a special option.

Daniel no longer works on Ubuntu's X server - that's why he unassigned
it from him.

Does this problem still exist in current Dapper?

I have same laptop,graphics (acer 1350, kn400) and it's running dapper.

3D works fine with or without the VBEModes option.

I can't comment on the VT switching problem because I can't switch between VT's! Ctrl-Alt-Fx does nothing. I have had this problem for a long time and I erroneously believed it was a trade off for having user switching in X. Perhaps that was true at one point, but it seems to be deprecated now. This happens with or without the VBEModes option.

My inittab looks fine and my Ctrl and Alt keys work.

I am not using any vga=xxx options at boot time. If I try and boot with vga=791 I get a blank screen. vga=791 has worked correctly in the past, but not at the moment.

Sometimes when I log out I get a blank screen and I have to do Ctrl-Alt-Backspace to reset things. This seems to have got worse recently - sometimes have to do this 2 or 3 times to get gdm login screen back.

Not sure if this is a kernel issue or a via driver issue or a combination of both. If there is a more appropriate bug report elsewhere, I couldn't find it.

I tried the new Flight6 live cd. I got a black screen as soon as GDM was started.

So the problem is not only that I get a black screen when switching to virtual consoles but also as soon as X server starts.

I have been using the VBEModes option for a few days now and and have not had any problems with blank screens after logoff since. I have also been able to switch VT's ok with chvt. Still no joy with Ctrl-Alt-Fn, but that's a seperate issue - there appear to be lots of xkb bug reports for that one.

I have done a bit of testing and found that disabling dri in xorg.conf also cures the problem, so perhaps this a kernel bug with the via drm module rather than a problem with the xorg via driver? Anyhow, until someone fixes this, the VBEModes option is the best workaround for now.

One last thing, the vga=791 boot option *is* neccessary for graphical boot with usplash. Otherwise usplash is garbled and you don't get to see gdm login screen. It does need to be disabled to boot to console in recovery mode though, otherwise you get a blank screen and you need to login and reboot blind. Hope I did not cause any confusion with my previous post - I was testing stuff in console mode and had forgotten I had set up grub to append the vga=791 option to the default kernel boot options.

There are numerous reports on seemingly identical issues, all related to the framebuffer VTs / consoles not working when X is run. This occurs with varying hardware (and varying kernel versions), so the issue may be wider than previously suspected, and possibly related to something that these occurrences have in common.

However, even as these reports have much in common, I am hesitant to mark any as duplicates, since the hardware varies (e.g. four different graphics cards), and because the cause may or may not be the same.

As I summarised these reports, I find it beneficial to attach the summary to each report. Apologies to recipients of Ubuntu Bugs & Ubuntu X SWAT for having to receive multiple copies of the same.

A brief summary follows:

Four reports, with the common behaviour that the framebuffer consoles stop working _as soon as X starts_:
- Bug 21416 - reported by felix.rommel. Acer Aspire 1350 with a Via KN400 Unichrome graphics card.
- Bug 29407 - unsure if original report is related or caused by a different issue, but all comments are related. Comments by Ignacio Lago Fontán, Compaq Evo N600c, ATI Radeon Mobility M6 LY; also by Thilo Six.
- Bug 40297 - reported by kko. Matrox G450 graphics card.
- Bug 42974 - reported by Richard Laager. HP dv800 with a GeForce Go 7400 graphics card.

A fifth report, with identical behaviour (fb stops working with X running), but only after hibernate + resume):
- Bug 36904 - reported by kamome with "dapper flight5 on a via mII12000".

A further report that may or may not be related, but lacks details (i.e. does the fb not work at all, or only stop working after X has been started? what equipment?):
- Bug 42168 - reported by vertiger.

Is this significant? Both in bug 21416 and bug 40297 the Xorg.0.log shows the following:

(II) Loading sub module "fb"
(II) LoadModule: "fb"
(II) Loading /usr/X11R6/lib/modules/libfb.a
Skipping "/usr/X11R6/lib/modules/libfb.a:fbmmx.o": No symbols found
(II) Module fb: vendor="X.Org Foundation"
 compiled for 6.8.2, module version = 1.0.0
 ABI class: X.Org ANSI C Emulation, version 0.2

On my system, libfb.a has the following details:
 -rw-r--r-- 1 root root 214592 2005-10-10 21:10 libfb.a

Even mc complains of "no symbols" for fbmmx.o if I take a look at libfb.a.

A further comment related to the previous.
File libfb.a belongs to package xserver-xorg-core:
$ dpkg -S libfb.a
xserver-xorg-core: /usr/X11R6/lib/modules/libfb.a

Is this still a problem in 7.04?

Yes - if I start with Feisty Desktop install CD I get a black screen of death.

As I wrote in comment 4 (https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-via/+bug/21416/comments/4) for this KN/KM400 chip there has to be an entry in xorg.conf in "Device" section:

Section "Device"
  ...
  Option "VBEModes" "true"
EndSection

I posted that solution 1,5 years ago - now I do not use this notebook as my primary computer any more.

It seems that this problem only occured on some Acer Aspire 135x configurations as Simon Hepburn wrote that he has NOT that problem.

My advice: add that option while configuring VIA KN/KM400 chipsets. But I wouldn't invest too much time in fixing an error of a very bad graphic card.

Please try 8.04.1 or 8.10alpha3 livecd, which use a different driver for VIA.

I received today a report from a friend to whom I gave an Ubuntu 8.04.1 CD to try to install on his wifes Acer Aspire 1353 LC that at some point during starup of the LiveCD the screen went black. Unfortunatly that's all the info I have and I could not be there to witness it first hand.

After my laptop flew out of my rucksack it is broken. I cannot make any comments about that laptop any more :( One last comment: I will never buy a device with a VIA graphic card again!

We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments.
Please reopen it if you can give us the missing information (as in, if it still exists!), To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New". Thanks again!