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    SubjectRe: [PATCH V3 0/3] PNP: Allow PNP resources to be disabled (interface)
    > On Sun, Jul 29, 2012 at 09:31:53PM +0200, Witold Szczeponik wrote:
    > > the aim is to select a PNP ACPI option where resources can be disabled
    > > (or are not needed). E.g., the parallel port of the 600E can be used
    > > with and without IRQ lines. The means to allow for this is to use the
    > > sysfs interface to select disabled resources (just like any other
    > > resource value). In https://lkml.org/lkml/2011/7/3/41, I used the
    > > following example:
    > >
    > > echo disable > /sys/bus/pnp/devices/$device/resources
    > > echo clear > /sys/bus/pnp/devices/$device/resources
    > > echo set irq disabled > /sys/bus/pnp/devices/$device/resources
    > > echo fill > /sys/bus/pnp/devices/$device/resources
    > > echo activate > /sys/bus/pnp/devices/$device/resources
    > >
    > > The third line is made possible by the patch series. All other
    > > lines are already implemented.
    >
    > Shouldn't this be rather "disable_irq" or something which is a single
    > word and thus would simplify parsing a lot?
    >
    > Also, <Documentation/filesystems/sysfs.txt> says
    >
    > "Attributes should be ASCII text files, preferably with only one value
    > per file. It is noted that it may not be efficient to contain only one
    > value per file, so it is socially acceptable to express an array of
    > values of the same type."
    >
    > Thanks.
    >
    > --
    > Regards/Gruss,
    > Boris.

    Hi Boris,

    the patch series is about adding the term "disabled" (or "<none") to
    the list of possible values for resources. The current state of the
    kernel ABI already allows to use the following statement (cf. DSDT
    excerpt from https://lkml.org/lkml/2011/7/3/41):

    echo set irq 7 > /sys/bus/pnp/devices/$device/resources

    i.e., the "resources" file can already parse all the values necessary for setting PNP values.

    The patch series is not about adding a new ABI or changing an existing ABI. It is about extending the existing one to be able to handle the term "disabled" (or "<none>") as a special for a resource value.

    --- Witold


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