Black screen on boot. When using vga=xxx option.

[Inox]

My post concerns Ubuntu Intrepid Ibex default kernels (2.6.27-2.3, 2.6.27-3.4 tested).

I can only see black screen during boot when using my favourite "vga=79"1 or "vga=792" options ("splash" and "quiet" removed from grub menu.lst option of course). Problem also affects Alt+F1,F2... terminals after boot. However "gdm" starts without any problems.

First observed such a behaviour on (early and final stage) Ubuntu 7.10 (there where no problems on 7.04 and 8.04).

To prove that the problem is in the kernel (not in the distro), I applied 2.6.27-2.3 kernel to my Ubuntu 8.04 what caused the black screen during boot. When 2.6.27-3.4 was published I repeated the procedure again with black screen as a result.

Test were carried out on nVidia GeForce 6600 GT and ATI Rage Mobility cards on totally different machines.

If you need debugging information please let me know. I assume attaching "lsusb", "lspci", "dmesg" results is pointless. What do you need then?

[Chris Coulson (chrisccoulson)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Unfortunately we can't fix it without more information.

Please include the following additional information (after booting with the "vga=xxx" option), if you have not already done so (pay attention to lspci's additional options), as required by the Ubuntu Kernel Team:
1. Please include the output of the command "uname -a" in your next response. It should be one, long line of text which includes the exact kernel version you're running, as well as the CPU architecture.
2. Please run the command "dmesg > dmesg.log" after a fresh boot and attach the resulting file "dmesg.log" to this bug report.
3. Please run the command "sudo lspci -vvnn > lspci-vvnn.log" and attach the resulting file "lspci-vvnn.log" to this bug report.

For your reference, the full description of procedures for kernel-related bug reports is available at https://wiki.ubuntu.com/KernelTeamBugPolicies Thanks in advance!

[Chris Coulson (chrisccoulson)]

Could you also please post the output of the following command after booting:

lsmod | grep fb

[Inox (inox)]

Hello Chris.
Thank you for your response. I attach all requested logs.
My current kernel is: Linux 2.6.27-3-generic #1 SMP.

[Chris Coulson (chrisccoulson)]

Thanks. This particular bug has already been reported and is a duplicate of bug 246269, so it is being marked as such. Feel free to continue to report any other bugs you may find.

[Inox (inox)]

Forgive me my mistake. The above logs were written after clean boot without vga=791 option.
You can find proper files in the attachment to this post.
Sorry.

[Chris Coulson (chrisccoulson)]

Thanks. That's ok - the first set of logs you sent contained what I was expecting to see anyway.

[Inox (inox)]

The workaround suggested by "captn" in this https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/246269 bug also worked for me :) on 2.6.27-4 -generic kernel. Thank you captn!

1) install: v86d
2) create: /etc/modprobe.d/uvesafb
with the following content (adjust resolution):
options uvesafb mode_option=1024x768-32 mtrr=3 scroll=ywrap
3) edit: /etc/modprobe.d/blacklist-framebuffer
add: blacklist uvesafb
3) edit: /etc/modules
add: uvesafb
4) run: update-initramfs -u
5) reboot

My results:
[ 19.124137] uvesafb: NVIDIA Corporation, GW-P/N@CVP945010MP0N0:0, GW-CLK@��
~
�, OEM: NVIDIA, VBE v3.0
[ 19.187599] uvesafb: protected mode interface info at c000:d2a0
[ 19.187651] uvesafb: pmi: set display start = c00cd2d6, set palette = c00cd340
[ 19.187710] uvesafb: pmi: ports = 3b4 3b5 3ba 3c0 3c1 3c4 3c5 3c6 3c7 3c8 3c9 3cc 3ce 3cf 3d0 3d1 3d2 3d3 3d4 3d5 3da
[ 19.195042] uvesafb: VBIOS/hardware supports DDC2 transfers
[ 19.347186] uvesafb: monitor limits: vf = 75 Hz, hf = 80 kHz, clk = 140 MHz
[ 19.347860] uvesafb: scrolling: ywrap using protected mode interface, yres_virtual=6144
[ 19.632556] uvesafb: framebuffer at 0xd8000000, mapped to 0xf9900000, using 24576k, total 131072k