# page fault while in kernel mode 8.0RC1 DVD



## Grey_Ash (Oct 18, 2009)

Hello,
     I have a problem while booting off the 8.0 RC1 DVD. It boots up and lists various devices and their drivers, but then the process conks out with: 

```
Fatal trap 12: page fault while in kernel mode
  cpuid = 0; acpi id = 00
  fault virtual address = 0x40
fault code = supervisor read data, page not present
```
    I tried option 2, but that hangs w/ "trying to mount / from /dev/md0" . I guess  that's because I'm booting from a usb dvd  drive.
          Any ideas of how to work around this and get 8.0 installed?


----------



## Tarick (Nov 28, 2009)

There is some problem with ACPI in 8.0, as I got this too on my Inspiron after upgrade. Submitted http://www.freebsd.org/cgi/query-pr.cgi?pr=140979 , please see if this is applicable for your situation too.


----------



## Grey_Ash (Nov 30, 2009)

Tarick said:
			
		

> There is some problem with ACPI in 8.0, as I got this too on my Inspiron after upgrade. Submitted http://www.freebsd.org/cgi/query-pr.cgi?pr=140979 , please see if this is applicable for your situation too.



Hello,
 I got this problem also while using the RC3 cd. I read the bug report, it seems to be the same problem! 
 I would like to test your fix. But I'm not familiar with the workings of the FreeBSD loader. When the cd has loaded the boot selections menu screen do I press e like in grub2 to edit loader.conf? Or something entirely different?
  Before going further Ill download the 8.0 stable release I think.
    Cheers and thanks for the tip! 

           grey


----------



## Grey_Ash (Nov 30, 2009)

Ah I think I found something:

*Press 6 in the boot menu: escape to loader prompt*


from another thread. So Ill try that.

 Cheers


----------



## Grey_Ash (Dec 11, 2009)

OK this fix you posted works for me! Thanks a million. I wonder what this device "ec" could be.


----------



## Beastie (Dec 11, 2009)

It's the ACPI embedded controller.

/usr/src/sys/modules/acpi/acpi/Makefile:


> # ACPI hardware drivers, mostly used for mobile systems.
> SRCS+=	acpi_acad.c acpi_battery.c acpi_cmbat.c acpi_cpu.c *acpi_ec.c*



The FreeBSD implementation: /usr/src/sys/dev/acpica/acpi_ec.c

More information at Phoenix Technologies website: http://www.phoenix.com/NR/rdonlyres/7A50B09F-47E1-45D1-912C-7A2F9EFEAAC8/0/acpiembed.pdf


----------



## Tarick (Dec 12, 2009)

Grey_Ash, could you please post what your hardware is? Currently fixing of this issue is moved to mail threads in freebsd-acpi and seems like stalled, probably new data could help it.


----------



## Grey_Ash (Dec 13, 2009)

Beastie said:
			
		

> It's the ACPI embedded controller.
> 
> /usr/src/sys/modules/acpi/acpi/Makefile:
> 
> ...


 
Hey, thanks for the information. Taking a read now.


----------



## Grey_Ash (Dec 13, 2009)

Tarick said:
			
		

> Grey_Ash, could you please post what your hardware is? Currently fixing of this issue is moved to mail threads in freebsd-acpi and seems like stalled, probably new data could help it.



The last email related to this is December 4 "panic in AcpiExReleaseMutex" ? 
Sure I'd be glad to. I'll subscribe.


----------



## Grey_Ash (Apr 21, 2010)

Due to school I wasn't able to keep up with the acpi list unfortunately, but recently I booted the same laptop off a memory stick image using the i386 arch with no problems. I wonder if this was a amd64 specific issue.
       Bye for now.


----------



## Tarick (Apr 21, 2010)

That's true, the problem doesn't appear on i386. I have the patch that fixes the crash on amd64, if you want it, I'm not sure that the fix will be included into 8.1. But on laptop it is better to use i386 if you don't have more than 4GiB of RAM.


----------



## Grey_Ash (Apr 22, 2010)

Hi Tarick,
From my readings I gather that 1501 would probably not support more than 4GB of ram. And i have a 1gb module & a 2gb module in it now.   So the i386 is the best choice. 
  Thanks for clearing that up about the page fault occurring only in x86-64, not i386.


----------



## Tarick (Apr 27, 2010)

Just FYI, the fix is in 8.0 Stable.


----------



## josetapadas (Jun 3, 2010)

Tarick said:
			
		

> Just FYI, the fix is in 8.0 Stable.



i'm getting the same error on 8.0 (i386) :\


----------



## Tarick (Jun 3, 2010)

josetapadas said:
			
		

> i'm getting the same error on 8.0 (i386) :\



Does the workaround works for you (i.e. disabling ACPI)? It could be the unrelated error.


----------



## josetapadas (Jun 4, 2010)

Tarick said:
			
		

> Does the workaround works for you (i.e. disabling ACPI)? It could be the unrelated error.



nope it does not :\

http://forums.freebsd.org/showthread.php?p=85989#post85989

could you help me?


----------



## Grey_Ash (Jun 4, 2010)

Actually the way around this when I was using amd64 was to boot off the 7.2-RELEASE cd and then customize the installation in sysinstall, specifying 8.0-RELEASE as the candidate. Installing took hours as I was downloading the install files off of the ftp site. I then  recompiled my fedora kernel to support ufs2 RW, and then mounted the relevant BSD partition, and  edited /boot/loader.conf :

Put into /boot/loader.conf:

```
debug.acpi.disabled="ec"
```

Rather involved but it worked. 
Good luck!

Grey


----------



## Grey_Ash (Jun 5, 2010)

Additionally I believe you could use the liveFS CD to mount the Free-BSD system after installing via the method I described above and access the /boot/loader.conf file that way. Use the 7.x series liveFS CD to avoid the kernel panic issue?


----------

