Re: [openib-general] Re: [PATCH 1/2] [IB/cm]: Correct CM port redirect reject codes

Grant Grundler
2005-08-04T01:36:45Z

On Wed, Aug 03, 2005 at 05:58:11PM -0700, yhlu wrote:
> Roland,
>
> In LinuxBIOS, If I enable the prefmem64 to use real 64 range. the IB
> driver in Kernel can not be loaded.

Can you provide a few more details about the configuration?
o kernel version
o architecture (i386 or x86-64)
o post the full console output from power up?

Recent email on linux-pci raised awareness that 32-bit kernel
can not support 64-bit PCI MMIO addresses. struct resource (defined in
include/linux/ioport.h) defines the start/end field as "unsigned long".
That's only 32-bit on i386 kernels.

> PCI: 04:00.0 18 <- [0xfcf0000000 - 0xfcf07fffff] prefmem64
> PCI: 04:00.0 20 <- [0xfce0000000 - 0xfcefffffff] prefmem64
I have to wonder if those BARs are truly prefetchable.
Does Mellanox assume CPU is the only one to write the 3rd BAR (RAM)
and the CPU implements a write-through cache (vs write back)?

I'm just guessing because I don't understand exactly how the
256MB of onboard RAM is accessed.

hth,
grant

>
> ib_mthca: Mellanox InfiniBand HCA driver v0.06 (June 23, 2005)
> ib_mthca: Initializing Mellanox Technologies MT25208 InfiniHost III Ex (Tavor c)
> ib_mthca 0000:04:00.0: Failed to initialize queue pair table, aborting.
> ib_mthca: probe of 0000:04:00.0 failed with error -16
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And I have to wonder if those BARs truly are prefetchable.
It would imply only the CPU writes them and