Re: [PATCH] PCMCIA / PM: Combine system resume callbacks

[Dominik Brodowski <linux@dominikbrodowski.net>]

On Tue, Feb 20, 2018 at 12:47:27PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> There is a problem with PCMCIA system resume callbacks with respect
> to suspend-to-idle in which the ->suspend_noirq() callback may be
> invoked after the ->resume_noirq() one without resuming the system
> entirely in some cases.  This doesn't work for PCMCIA because of
> the lack of symmetry between its system suspend and system resume
> "noirq" callbacks.
> 
> The system resume handling in PCMCIA is split between
> socket_early_resume() and socket_late_resume() which are called in
> different phases of system resume and both need to run for
> socket_suspend() (invoked by the system suspend "noirq" callback)
> to work.  Specifically, socket_suspend() returns an error when
> called after socket_early_resume() without socket_late_resume(),
> so if the suspend-to-idle core detects a spurious wakeup event and
> attempts to put the system back to sleep, that is aborted by the
> error coming from socket_suspend().
> 
> This design doesn't follow the power management documentation
> stating that the "noirq" resume callback is expected to reverse
> the changes made by the "noirq" suspend one.  Moreover, I don't see
> a reason for splitting the PCMCIA socket system resume handling this
> way

Unless I am mistaken, this split was introduced by commit
9905d1b411946 . So we should take into account the reasons stated
in that commit message.

Thanks,
	Dominik