> I'm worried by this... At no point do you check the host bridge
 > capabilities, and thus will happily set the max read req size to some
 > value larger than the max the host bridge can cope...

Well, it's disabled by default... the option is there as a quick way
to fix "why is my bandwidth so low" when a broken BIOS sets these to
minimum values.  Maybe we should just strip out that code and point
people who want to tweak this at setpci instead.

 > So for PCI-X, if we want tat, we need a pcibios hook for the platform
 > to validate the size requested. For PCI-E, we can use standard code to
 > look for the root complex (and bridges on the path to it) and get the
 > proper max value.

Actually even PCIe might not be that easy.  For example with current
kernels on PowerPC 440SPe (SoC with PCIe), I just get:

    # lspci
    00:01.0 InfiniBand: Mellanox Technology: Unknown device 6274 (rev a0)

ie no host bridge / root complex.

 - R.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to