On Thu, May 06, 2021 at 04:48:42PM -0500, Bjorn Helgaas wrote:
> On Thu, May 06, 2021 at 08:38:20PM +0300, Konstantin Kharlamov wrote:
> > On Macbook 2013 resuming from s2idle results in external monitor no
> > longer being detected, and dmesg having errors like:
> >
> > pcieport 0000:06:00.0: can't change power state from D3hot to D0 (config space inaccessible)
> >
> > and a stacktrace. The reason turned out that the hw that the quirk
> > powers off does not get powered on back on resume.
>
> quirk_apple_poweroff_thunderbolt() was added in 2014 by 1df5172c5c25
> ("PCI: Suspend/resume quirks for Apple thunderbolt"). It claims
> "power is automatically restored before resume," so there must be
> something special about s2idle that prevents the power-on.
With s2idle, the machine isn't suspended via ACPI, so the AML code
which powers the controller off isn't executed. The dance to prepare
the controller for power-off consequently isn't necessary but rather
harmful.
To get the same power savings as with ACPI suspend, the controller
needs to be powered off via runtime suspend. I posted patches for
that back in 2016. I'm using them on my laptop, they need some
polishing and rebasing before I can repost them due to massive
changes that have happened in the thunderbolt driver in the meantime.
Without these patches, the controller sucks 1.5W of power in s2idle.
> Obviously the *hardware* hasn't changed since 1df5172c5c25. Is s2idle
> something that wasn't tested back then, or is this problem connected
> to an s2idle change since then? Can we identify a commit that
> introduced this problem? That would help with backporting or stable
> tags.
Yes I believe the quirk predates the introduction of s2idle by a couple
of years.
> > Signed-off-by: Konstantin Kharlamov <Hi-Angel@xxxxxxxxx>
Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>
The patch looks fine to me.
Thanks,
Lukas
