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    SubjectRe: [PATCH] i2c-scmi: Quirk to work on IBM machines with broken BIOSes
    On Wed, Oct 21, 2009 at 08:57:13AM -0600, Bjorn Helgaas wrote:
    > On Tuesday 20 October 2009 08:30:16 pm Crane Cai wrote:
    > > Hi Darrick,
    > >
    > > On Tue, Oct 20, 2009 at 04:11:49PM -0700, Darrick J. Wong wrote:
    > > > On some old IBM workstations and desktop computers, the BIOS presents in
    > > > the DSDT an SMBus object that is missing the HID identifier that the
    > > > i2c-scmi driver looks for. It also omits the leading "_" in the method
    > > > names (it should be _SBR, not SBR_). Modify the ACPI device scan code to
    > > > insert the missing HID if it finds an IBM system with such an object, and
    > > > modify the i2c-scmi driver to handle the odd method names.
    > > I have a suggestion: You can need not to add quirk in acpi part, instead
    > > you can add your ACPI device HID in i2c-scmi with your specificied methods
    > > set.

    The problem is that the BIOS does not provide an HID for the SMBus object at

    > Maybe Darrick understands your suggestion, but I don't. The only way
    > i2c-scmi ever learns about a device is when acpi_smbus_cmi_add() is
    > called, and that's only called when the Linux/ACPI core has found a
    > device that matches "SMBUS01".
    > Can you elaborate on your suggestion?
    > The i2c-scmi driver *could* walk the whole namespace itself, looking
    > for devices with the SBI/SBR/SBW methods, but I like Darrick's quirk
    > approach better because it allows i2c-scmi to continue to use the
    > normal ACPI driver model.

    ...which is why I need the quirk to stuff one in at the OS level. Were it as
    simple as recognizing a different HID, I could have written a less intrusive
    patch. :/


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