Blank Screen after loading Kubuntu logo

[mbwd1]

I am on an ASUS Q501LA laptop, latest build of Kubuntu. I have been wrangling with Kubuntu for about a month now, and I finally got almost everything set up to my liking (still can't get A2DP bluetooth working). Of course, I made one more change before backing it up (I installed a Panel at the bottom of the screen WITH Cairo-Dock) -- and after waking from a sleep the touchpad was dead (actually, I had also edited the synaptics file). So I used the keyboard to quit all programs and reboot.

I got to the Grub menu and loaded into Kubuntu as usual. I got the nice Kubuntu logo for about five seconds. Then the screen just goes blank (slightly purply background if you look at the right angle). I can get back to Grub, but the same thing happens no matter which Kubuntu variant (even generic) I load.

I did some searches for aid, but the other blank screens of death posts seem to concern Grub errors -- and I can get to and use grub fine.

I did exit to the command line and looked at: /var/log/Xorg.0.log. One problem is that I keep getting an error stating:

[535.184202] usb 1-7: unable to read config index descriptor/start: -71 
[535.184323] usb 1-7: can't read configurations, error -71

And this keeps repeating down the screen, even over the terminal I am using. So I lose the screen very quickly.

If I move quickly, I can read the /var/log/Xorg.0.log file. Here are the EE's:

parse error on line 12 of section  /usr/share/X11/xorg.conf.d/60-synaptics-options.conf
InputClass  "5" is not a valid keyword in this section
(EE) Problem parsing the config file
(EE) error parsing the config file
(EE) fatal server error:  no screens

I also looked at /var/log/dmesg, and found this:

No AGP bridge found
Calgary:  detecting Clagary via BIOS EDBA area
Calgary:  Unable to locate Rio Grande Table in EDBA -- Bailing!
[cut here]
WARNING:  CPU: 0 PID: 0 at /build/buildd/linux-3.11.0/drivers/iommu/dmar.c:488 warn_invalid_dmar+0x7e/0x90()
Your BIOS is broken; DMAR reported at address 0!

Any ideas what to do? I can't get into the desktop at all.

[mbwd1]

I was able to figure the critical part of this out: I had a missing quotation mark in my 60-synaptics-options.conf file (which I created to fine-tune the touchpad).

I was able to edit the file in the terminal at boot and everything was fixed ---- except the recurring

[535.184202] usb 1-7: unable to read config index descriptor/start: -71 
[535.184323] usb 1-7: can't read configurations, error -71

This made it really difficult to find and fix the error because I was racing against time as these errors populated my screen.

Any way to fix this scrolling error?

And do I need to worry about my BIOS being reported as broken?

[oshunluvr]

What's attached to USB 1-7?

Try pulling all your USB devices and rebooting. If the error goes away, start using them one at a time and see which one is causing the problems.

[oshunluvr]

The BIOS error seems harmless

https://bugs.launchpad.net/ubuntu/+s...ux/+bug/252354

[mbwd1]

Thanks for the idea -- but I don't have (and haven't had) any USB devices attached!

[oshunluvr]

Nothing? Are you able to get to the desktop yet? Try dumping lsusb output to a text file so you can read it.

lsusb > lsusb.txt

[oshunluvr]

Look in you BIOS for a setting labeled IOMMU. Toggle it (on if it's off, or off if it's on) and rebooting.

[mbwd1]

No, nothing -- no USBs. Here is the lsusb:

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 006: ID 0bda:0139 Realtek Semiconductor Corp. RTS5139 Card Reader Controller
Bus 001 Device 011: ID 04f3:010c Elan Microelectronics Corp. 
Bus 001 Device 003: ID 04f2:b3fd Chicony Electronics Co., Ltd 
Bus 001 Device 002: ID 8087:07dc Intel Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I am back into the desktop. I will try to look for IOMMU in the BIOS (don't remember seeing that, but will have a look).

[mbwd1]

Nothing called IOMMU in my BIOS. But I believe this has to do with Virtualization. I disabled the Intel Virtualization option, and I think that did it!! Thanks.

[oshunluvr]

Ok, try this: Reboot. When you see the grub menu, hit "e" to edit the line. Add this after "quiet splash"

usbcore.old_scheme_first=1

and then continue the boot. If this works, do the above edit to /etc/default/grub and then run update-grub to make it permanent.

[mbwd1]

Thanks again.