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    SubjectRe: [PATCH] ALSA: hda-intel - Disable MSI support by default
    Linus Torvalds wrote:
    > However, I really think that this should be a generic PCI layer thing. If
    > some device asks for MSI interrupts, the PCI layer should try to turn off
    > a INTx routing on its own. Asking drivers to do both is just silly,
    > especially since driver writers really shouldn't be expected to know about
    > all these issues (sure, the best ones do, but a lot of driver writers will
    > just say "it works for me").
    >
    > So I don't think the HDA driver should need disable INTx on its own
    > explicitly.

    Your thinking is correct, but there is one hitch.

    As Roland noted, PCI layer /already/ does this for PCI-Express devices.

    The reason we cannot do this in the generic layer for non-PCI-Ex is only
    the driver knows whether that PCI 2.2 bit was actually implemented in
    the device or mapped to some other weird behavior we don't want to
    touch. DISABLE-INTX is a new bit not present in PCI 2.1 (alas!!).

    pci_intx() was my five minute solution to this problem, and it got moved
    outside of libata as soon as somebody needed the same thing :)

    Maybe a better solution is letting the driver say "pci_dev->intx_ok = 1"
    right before it calls pci_enable_device().

    And if we do this, we can follow through on another suggestion I made:
    disabling INTx on driver exit, to help eliminate any possibility of
    screaming interrupts after driver unload.

    Jeff


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