Re: [PATCH V3 0/3] PNP: Allow PNP resources to be disabled (interface)

From: Rafael J. Wysocki
Date: Sun Jul 29 2012 - 15:16:37 EST


Hi,

On Sunday, July 29, 2012, Witold Szczeponik wrote:
> Hello everybody,
>
> this simple patch series continues the work begun in commit
> 18fd470a48396c8795ba7256c5973e92ffa25cb3 where ACPI PNP resource templates
> with empty/disabled resources are handled.
>
> The aim of this patch series is to allow to set resources as "disabled" using
> the "/sys/bus/pnp/devices/*/resources" interface. Such "disabled" resources
> are needed by some vintage IBM ThinkPads like the 600E where some devices need
> to have their IRQs disabled in order to support all the devices the 600E has.
>
> To better understand the motivation, let's look at an excerpt from the 600E's
> DSDT:
>
> Name (PLPT, ResourceTemplate ()
> {
> StartDependentFnNoPri ()
> {
> IO (Decode16, 0x03BC, 0x03BC, 0x01, 0x04)
> IRQNoFlags () {7}
> }
> /* Some entries deleted */
> StartDependentFnNoPri ()
> {
> IO (Decode16, 0x03BC, 0x03BC, 0x01, 0x04)
> IRQNoFlags () {}
> }
> EndDependentFn ()
> })
>
> As one can see, the IRQ line for the last option is empty/disabled. Also, both
> options share the same priority, meaning they are equal alternatives. In order
> to be able to use the IRQ 7 for some other device, it is necessary to select
> the second option, which can be done with the patch series applied.

Do I understand correctly that you want to disable those things through
sysfs?

Rafael
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