RE: [PATCH] pci-mmconfig fix for 2.6.9

From: Michael Chan
Date: Mon Nov 15 2004 - 02:09:02 EST


Grant Grundler wrote:

> There are two tests in arch/i386/pci/mmconfig.c:pci_mmcfg_init() before
> the raw_pci_ops is set to &pci_mmcfg. Perhaps some additional crude tests
> could select a different set of pci_raw_ops to deal with posted writes
> to mmconfig space. Someone more familiar with those chipsets might
> find a more elegant solution.

Do you mean something like pci_mmcfg1 for Intel chipsets that implement non-posted mmconfig and pci_mmcfg2 for other chipsets that may implement posted mmconfig? pci_mmcfg2's write method will guarantee that the write has reached the target before returning. If pci_mmcfg2's write method uses read from the target to flush the write, we are back to the original problem of out-of-spec read when writing the PMCSR register. If the flush does not require reading from the target device, then it's fine.

Michael




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