run resume code only for S1-S4 states

[Jung-uk Kim]

On Tuesday 14 April 2009 11:58 am, Andriy Gapon wrote:
> Guys,
> could you please review the attached patch?
>
> Its main idea is to make control flow of acpi_EnterSleepState
> similar to that of acpi_ReqSleepState: reject invalid state
> parameter immediately and handle special S5 as early as possible.
> Primary purpose is to avoid running resume code when it is not
> necessary - e.g. shutdown_nice() typically returns immediately
> after initiating a graceful shutdown by sending a signal to init.

I tried to solve this problem once.  To preserve the current 
behaviour, you have to clean up sc->acpi_next_sstate and set 
sc->acpi_sstate to S5 as well if my memory serves.

> As such, S5 is handled right after checking/disabling re-entry.
> switch becomes unneeded, because all remaining possibilities are
> grouped into a single case. I decided to use do-while(0) statement
> in the place of the switch for the following reasons:
> 1. minimize diff by preserving indentation
> 2. minimize diff by preserving control flow that depends on break
> statement But I am not sure how this while(0) corresponds with
> style(9), I couldn't find any reference in the manual page.

I think goto is more cleaner and easy to read in this case.

> There is also a concern about calling shutdown_nice() outside of
> the Giant lock and binding to CPU 0. I am not sure about the
> pre-requisites for this function. John, maybe you could help me
> here?

I think you don't need giant here and CPU binding is done from boot().

Jung-uk Kim