Re: How to enable auto-suspend by default

From: Bastien Nocera
Date: Tue Nov 24 2020 - 10:53:25 EST


On Tue, 2020-11-24 at 14:37 +0200, Mathias Nyman wrote:
> <snip>
> I don't think we are ready to enable runtime pm as default for all
> Intel xHCI controllers.
> The risk of xHCI not waking up when user plugs a mouse/keyboard,
> making the system unusable
> just seems too high compared to the powersaving benefit.
>
> The powersaving benefit from autosuspending the TCSS xHCI is a lot
> better, and we, (Mika mostly)
> has been able to verify they work.
>
> So I propose we for now continue adding TCSS xHCI controllers to the
> allowlist in kernel.
> For others I think a userspace allow/denylist makes sense.
>
> Long term goal would be default allow for all, with short denylist in
> kernel.

Is there any way to preemptively enable autosuspend for all the _TCSS_
xHCI controllers?

This was the problem the original post tried to tease out, whether it
would be easier/better to enable autosuspend by default, and not enable
it on systems where it breaks something, rather than default to sucking
battery until somebody notices that a device ID got missed.