Messages in this thread | | | Subject | Re: [PATCH 4/6] MTHCA driver (infiniband) use new pci interfaces | From | Roland Dreier <> | Date | Mon, 11 Dec 2006 17:38:24 -0800 |
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> 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.
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