Messages in this thread | | | Date | Tue, 28 Feb 2023 10:03:22 +0100 | Subject | Re: [PATCH] HID: usbhid: enable remote wakeup for mice | From | Oliver Neukum <> |
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On 23.02.23 20:41, Limonciello, Mario wrote:
Hi,
>> As a system wakeup source a mouse that generates events when >> it is moved, however, would make the system unsuspendable, whenever >> even >> a bit of vibration is acting on the system. >> And as S4 is used in many setups to prevent an uncontrolled shutdown >> at low power, this must work. > > At least in my version of the series, this is part of the reason that it was > only intended to be used with s2idle.
Yes, that is sensible. If these patches are to be taken at all, that will be a necessary condition to meet. But it is not sufficient.
> The kernel driver is well aware of what power state you're in the suspend > callback (pm_suspend_target_state). > > What about if we agreed to treat this one special by examining that? > > If the sysfs is set to "enabled"
If user space needs to manipulate sysfs at all, we can have user space tell kernel space exactly what to do. Hence I see no point in conditional interpretations values in sysfs at that point.
We are discussing the kernel's default here.
> * During suspend if your target is s2idle -> program it > * During suspend if your target is mem -> disable it > * During suspend if your target is hibernate -> disable it
To my mind these defaults make sense. However, do they make much more sense than what we are doing now?
> With that type of policy on how to handle the suspend call in place > perhaps we could set it to enabled by default?
It pains me to say, but I am afraid in that regard the only decision that will not cause ugly surprises is to follow Windows. Yet, what is wrong about the current defaults?
> Turning on "autosuspend" for USB mice makes them behave pretty > similarly to how they work when they're marked for remote wakeup.
Because it is exactly the same mechanism.
> On some mice the lasers turn off, and they only wakeup when you > press a button or roll a wheel.
Yes. And _some_ is the exact problem. If we could tell, _how_ mice react, this discussion were unnecessary.
Regards Oliver
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