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    SubjectRe: pci_enable_msi() for everyone?
    On Sat, Jun 04, 2005 at 12:18:03AM -0700, Greg KH wrote:
    > On Sat, Jun 04, 2005 at 01:05:37AM -0600, Grant Grundler wrote:
    > > On Fri, Jun 03, 2005 at 11:48:21PM -0700, Greg KH wrote:
    > > > > One complication is some drivers will want to register a different
    > > > > IRQ handler depending on if MSI is enabled or not.
    > > >
    > > > That's fine, they can always check the device capabilities and do that.
    > >
    > > Can you be more specific?
    > > Maybe a short chunk of psuedo code?
    >
    > Hm, here's a possible function to do it (typed into my email client, not
    > compiled, no warranties, etc...):
    >
    > /* returns 1 if device is in MSI mode, 0 otherwise */
    > int pci_in_msi_mode(struct pci_dev *dev)
    > {
    > int pos;
    > u16 control;
    >
    > pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
    > if (!pos)
    > return 0;
    > pci_read_config_word(dev, msi_control_reg(pos), &control);
    > if (control & PCI_MSI_FLAGS_ENABLE);
    > return 1;
    > return 0;
    > }

    What if MSI support has been disabled in the bridge due to some quirk
    (like the recent AMD 8111 quirk) ? Maybe the above function
    should check pci_msi_enable as well ?

    Dave

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