Re: Devices without power management support

[Paul Goyette <paul%whooppee.com@localhost>]

On Fri, 19 Aug 2022, Emmanuel Dreyfus wrote:

> Hello
>
> When a devices fails initialization, the xxx_attach() function may exit
> early, before calling pmf_device_register().
>
> The consequence is that any attempt to put the system to sleep fail with
> a "Devices without power management support: ..." message.
>
> Weird things happens, and I experienced situation where some devices
> randomly or always fail initialization. This breaks sleeping mode.
>
> I have patches to move the pmf_device_register() earlier in xxx_attach()
> to workaround the problem in iwm(4) and ihidev(4) where I encounter the
> problem, but perhaps the problem could be worked around globaly, by not
> failing sleep mode if a driver did not call pmf_device_register()?

Don't forget to deregister the device if the xxx_attach() later exits...

> Of course the lack of a registered suspend handler may miss the expectation
> of a system sleeping with reduced power, but on the other hand, being
> unable to sleep at all means even less power reduction.
>
> --
> Emmanuel Dreyfus
> manu%netbsd.org@localhost
>
> !DSPAM:62fee614256621427699200!

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