problems with ACPI

spuzzzzzzz · 09-04-2004, 05:40 PM

For the past few weeks, I've been experiencing random lockups in which the keyboard, mouse and screen stop responding (but ssh'ing to the affected computer still works). I think the problem is related to ACPI so I added "acpi=off" to my boot parameters. This caused my video to go horribly slow--my fps in games halved and it took about a second to redraw the screen when I switch virtual desktops (on a GeForce 6800GT). There is also a slight difference in dmesg that I think might be related:
with "acpi=off"

Code:

kernel was compiled with IOMMU_GART support, disabling NVAGP!

without "acpi=off"

Code:

agpgart: Found an AGP 3.0 compliant device at 0000:04:00.0.
agpgart: Putting AGP V3 device at 0000:04:00.0 into 8x mode
agpgart: Putting AGP V3 device at 0000:05:00.0 into 8x mode

Any ideas? Also, is there anything that would give more information about these lockups? I can still ssh to the box so I can retrieve any information from dmesg or /proc or whatever--I just don't really know what to look for.

TIA

mkaman · 09-04-2004, 06:14 PM

If you search for more info look in the log directory. In my rh9 is under /var/log there you will find the logs for the system.

I don't know what is that iommu_gart support that get's enabled when acpi is off but i know that is some type of gart controler for the agp and displaces the one provided by nvidia. You colud try to recompile your kernel disabling that module in the compilation or you can dig into google for iommu info.
Maybe you can search the documentation of your current kernel and see if you can enable some boot option that will help you.

I've read somewhere that you can try one of these options as a kernel boot option:
iommu=off (This is advised to crash the boot with a kernel panic)
iommu=noagp (Maybe this is for you)

Regards

spuzzzzzzz · 09-04-2004, 07:13 PM

Thanks for the suggestions. Unfortunately, I can't get useful stuff from my logs until it crashes again, so I won't follow that suggestion up just yet (and hopefully not for a while

). IOMMU is compiled into my kernel--i think it's an x86-64 specific option. It allows the addressing of 32-bit PCI when there is more than 4 GB of memory. I only have 2GB but the help option says I should compile it in anyway since it will be disabled if not needed. Indeed, dmesg reveals "PCI-DMA: Disabling IOMMU". IOMMU is not available as a module. I'll try the boot options tonight--the computer is acting as a file server so I can't just reboot at random times.

As for agpgart, there is no option to leave it out. menuconfig just shows "---" instead of a tick box.

Code:

#grep AGP .config
CONFIG_AGP=y
CONFIG_AGP_AMD64=y
# CONFIG_AGP_INTEL_MCH is not set

spuzzzzzzz · 09-05-2004, 06:05 PM

I tried booting with "iommu=noagp acpi=off" and it gave me the same message about IOMMU_GART. I even disabled IOMMU in the kernel and recompiled but it gave me the same message when I used "acpi=off"