http://bugzilla.kernel.org/show_bug.cgi?id=11714
------- Comment #48 from [EMAIL PROTECTED] 2008-11-01 17:01 ------- I have been looking at the diagnostic information I have just posted. Two things are prominent in the new kernel panic output: 1) it now says BUG: unable to handle kernel NULL pointer dereference at 00000000 2) it now also says Aperture pointing to e820 RAM. Ignoring. Your BIOS doesn't leave a memory aperture hole. Please enable the IOMMU option in the BIOS setup. This costs you 64 MB of RAM. There is more information about the aperture problem in the dmesg output: [ 0.010000] Node 0: aperture @ 8174000000 size 32 MB [ 0.010000] Aperture beyond 4GB. Ignoring. [ 0.010000] Your BIOS doesn't leave a aperture memory hole [ 0.010000] Please enable the IOMMU option in the BIOS setup [ 0.010000] This costs you 64 MB of RAM [ 0.010000] Mapping aperture over 65536 KB of RAM @ 20000000 [ 0.010000] PM: Registered nosave memory: 0000000020000000 - 0000000024000000 I don't know if the latter problem is causing the kernel panic, but I decided to try to resolve it in case it is. I have had a look around the ASUS M3A-H/HDMI bios setup, but I can't find any IOMMU option. I did a internet search and I came up with a discussion (http://vip.asus.com/forum/view.aspx?id=20080110054618984&board_id=1&model=M2NPV-VM&page=1&SLanguage=en-us) which pointed me to an information source (ftp://download.nvidia.com/XFree86/Linux-x86/1.0-8174/README/32bit_html/appendix-l.html) which says: "On AMD's AMD64 platform, the size of the IOMMU can be configured in the system BIOS or, if no IOMMU BIOS option is available, using the 'iommu=memaper' kernel parameter. This kernel parameter expects an order and instructs the Linux kernel to create an IOMMU of size 32MB^order overlapping physical memory. If the system's default IOMMU is smaller than 64MB, the Linux kernel automatically replaces it with a 64MB IOMMU." So, it looks like I might be able to use boot parameters to sort out this problem. I have looked up the iommu boot parameters in the kernel documentation (http://www.kernel.org/doc/Documentation/kernel-parameters.txt) and found the following potentially relevant parameters: iommu= [x86] off force noforce biomerge panic nopanic merge nomerge forcesac soft amd_iommu= [HW,X86-84] Pass parameters to the AMD IOMMU driver in the system. Possible values are: isolate - enable device isolation (each device, as far as possible, will get its own protection domain) amd_iommu_size= [HW,X86-64] Define the size of the aperture for the AMD IOMMU driver. Possible values are: '32M', '64M' (default), '128M', '256M', '512M', '1G' The 'iommu=memaper' option is not mentioned in the official documentation. I am not sure what the bios and dmesg diagnostic messages are asking me to do with these boot parameters. Please can someone advise me how I should use the iommu boot parameters? iommu=force ? Thank you. -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ acpi-bugzilla mailing list acpi-bugzilla@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla
