FC6 kernels & 4GB of memory

[Darryl]

Darryl wrote:
> I tried downloading the latest/greatest 2.6.21 kernel and compiling my 
> own 32bit "PAE" & "regular" kernels but they did the same thing. 
> "regular" sees all the memory but tells me to use a PAE kernel and "PAE" 
>  won't use all the memory and crashes on boot without mem=4095m. A 
> little frustrating since the "regular" kernel and memtest86 see all the 
> memory. The good news is that the on-board NIC is natively supported in 
> .21 though :-/
> 

I found a year-old posting from Andi Kleen that suggested using 
'iommu=force' for a VIA chipset and it actually worked :-) In the 64bit 
kernel anyway. The atl1 driver for the on-board NIC works in the 64bit 
kernel too but seems to make the machine reboot when doing a DHCP 
request for an IP address on 32bit kernels. I'd prefer to stick with 
32bit though...