kernel panic with greater that 8 GB of memory

Steve Kargl sgk at
Mon Nov 29 13:53:22 PST 2004

On Mon, Nov 29, 2004 at 03:41:41PM -0600, James R. Van Artsalen wrote:
> I'm not convinced that the bounce-buffer scheme works on amd64 at all.  
> I don't think twe, ata or bge work (individually or in combination) with 
> more than 4GB of RAM.

8GB of RAM seems to work without a problem.

> Are you using a bge NIC or USB, or any other driver that needs bounce 
> buffer, 1394?  Which SCSI driver?

The K8S Pro has 2 bge nics on the motherboard.  I have the driver
in the kernel, but neither nic is currently being used.  USB is
compiled into the kernel and is only used when I transfer files
to a memory stick (ie., it's seldomly used).  Two SCSI drives
are attached to an Adaptec AIC7902 Ultra320 SCSI adapter that
is also on the motherboard.

> Is this 5.3 release?  5.2.1 worked for me.  The bounce-buffer code in 
> amd64 has changed since then but I haven't been able to figure it out.

6.0-CURRENT from today's sources, but the problem goes back to
at least August.  You can find other posts by me about panics 
with >8GB or ram.


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