[openib-general] Re: mthca and LinuxBIOS

[yhlu]

The mellanox can use prefmem64, but the BIOS could only allocate the
some range below 4G, So 32 bit OS still can use the IB cards.
but for 64bit OS, We could allocate range above 4G (0xfc00000000), So
the mmio below 4G can be smaller. ( for example from 512M to 128M, the
user can get back some RAM back if Opteron don't have hardware memhole
support).

YH



On 8/4/05, Roland Dreier <rolandd at cisco.com> wrote:
> >>>>> "yhlu" == yhlu  <yhlu.kernel at gmail.com> writes:
> 
>     yhlu> YES.  I will send you the output message later about
>     yhlu> "CONFIG_INFINIBAND_MTHCA_DEBUG=y"
> 
> Thanks.  In the meantime, can you explain what it means to "enable the
> prefmem64 to use real 64 range"?  What is the difference between this
> and the configuration that works?
> 
>  - R.
>