Solved Need help to recover from bug 193613

N

noir

Hi all, the name's Christian, and I do feel bad that my first post on this forum is a new thread, but I could not find an answer for myself, nor in #freebsd.

Here's the situation:
  • I'm new to FreeBSD, and gave a -CURRENT snapshot a try.
  • Installation to a Gigabyte IvyBridge BRIX (intel 3337 mobile chip with HD4000 graphics) went perfectly, I chose encrypted ZFS root as setup.
  • Then I switched from syscons to vt in loader.conf, it loads nicely.
  • A kldload of the i195 KMS worked fine too, and the resolution switched to native display resolution.
  • Then I added
    Code: 
    i915kms_load="YES"
    to loader.conf, and seemingly triggered bug 193613, meaning I get a black screen and kernel panic during boot.
Now I thought there were two scenarios available to make the system work again:
  1. tell loader.conf to ignore or disable the i915 KMS load;
  2. mount the boot partition in a Live environment and fix loader.conf .
    • I struggled with the "(3) Escape to loader" prompt:
      Code: 
      set i915kms_load="NO"
      had no impact.
    • Neither did unloading.
    • show told me that loader.conf was defined as a variable, but I did not manage to access the file or change variables.
    • The memory stick I had used to install FreeBSD allowed me to boot into the LiveCD environment.
    • Here a zpool import ada0p2 worked as a pool import (the pool appeared as well on zpool list as on zfs list).
    • The file system of said LiveCD is write-only though, and I could not get ZFS to mount boot to /bootloader. I could not manually create the directory either.
    • My feeble attempts to create a tmpfs partition to mount /bootloader there were also futile.
Did I miss something obvious? What solution would you propose? I could have done a re-install easily in the time it took to do this research, but I want to learn FreeBSD and grow capable of correcting such errors.

Thanks for your help!
 
My sincere apologies, I wrongfully thought that said bug also applied to -RELEASE. I will switch back a.s.a.p.

In case I were to encounter similar problems with loader.conf later, is there a recommended rescue system to mount ZFS /bootloader? There is Fixit, but the articles seem dated.
 
Hi Juanitou, thanks a lot for the reply!

I tried unset i915kms_load, but it just gave me:
Code: 
no such file or directory

To further things, I did a show, and there was one variable that looked interesting:
Code: 
loader_conf_files=/boot/device.hints /boot/loader.conf /boot/loader.conf.local

unset loader_conf_files seemed successful, but as soon as I issued boot, vt(4) as well as i915kms loaded up again and I was stuck again at the black screen.
 
noir said:
I tried unset i915kms_load, but it just gave me:
Code: 
no such file or directory
Click to expand...
This error means that the variable is not set, so maybe you mistyped the command. Double-check the output of the show and unset i915kms_load commands. For the latter, successfully unsetting a variable just prints nothing. Also, you could try set loader_conf_files="[I]/boot/loader.conf.local[/I]".
 
Wait, hold on, stop.

vt(4) is built into the GENERIC kernel in -CURRENT. The KMS modules might not be loaded if you set text mode:
/boot/loader.conf:
Code: 
hw.vga.textmode=1

If that does not work, use sc(4) instead:
/boot/loader.conf:
Code: 
kern.vty=sc
 
Juanitou: I tried both of your suggestions, unfortunately the errors persisted.

wblock@: I also tried both of yours, I felt that they had to work; unfortunately I still get a black screen.

I did make sure that show had the variables set or unset. Still no dice.

I think it is time for me to do a quick install of -RELEASE and try KMS there. Thanks so much for your time and help!
 
Thanks so much Juanitou, this worked perfectly! I was able to remove the entry from loader.conf.

By the way, the same error persists on RELEASE 10.1, I just tried.
 
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