Re: [RFC] USB/PM: should USB interface drivers distinguish hibernation THAW from RESTORE?

[Oliver Neukum <oneukum@suse.com>]

On 30.04.26 04:14, Haowen Tu wrote:
Hi,

  
> But after your replies, I agree that this is not really a USB-specific
> problem. The more fundamental question seems to be whether, in the
> current S4 flow, resuming the full device set at that point is the
> intended model, or whether there is any room for resuming only the
> subset of devices needed for image writeout and whatever else must
> remain functional during that phase.

In principle you could do so. Your problem would be
a) computing the subset of devices that need not be thawed
b) error handling

>    1. a full THAW of the suspended system, as it is today, or
>    2. potentially a narrower resume of only the devices needed for
>       writeout, followed by broader recovery only if writeout fails.

Well, that is a question of motivation. Why do you want to avoid
thawing devices? What advantage justifies deviating from the simple
model?

If you really wanted to do this, the implementation would be rather
straight forward. The difficult question is deciding whether you
want to do it at all. Do you have systems in which going STD is
critical in terms of performance?

	Regards
		Oliver