On Mon, 16 Oct 2017, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> The motivation for this change is to provide a way to work around
> a problem with the direct-complete mechanism used for avoiding
> system suspend/resume handling for devices in runtime suspend.
>
> The problem is that some middle layer code (the PCI bus type and
> the ACPI PM domain in particular) returns positive values from its
> system suspend ->prepare callbacks regardless of whether the driver's
> ->prepare returns a positive value or 0, which effectively prevents
> drivers from being able to control the direct-complete feature.
> Some drivers need that control, however, and the PCI bus type has
> grown its own flag to deal with this issue, but since it is not
> limited to PCI, it is better to address it by adding driver flags at
> the core level.
I'm curious: Why does the PCI bus type (and others) do this? Why
doesn't it do what the driver says to do?
Alan Stern
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