Re: [rfc/rft]power management for btusb

Alan Stern
2008-08-20T15:35:20Z

On Wed, 20 Aug 2008, Marcel Holtmann wrote:

> finally I found the device and setting it to auto makes it actually
> suspend. Why is this not default? The driver has to enable it anyway.

If there's no driver then it would take effect right away. This causes
problems for devices during startup -- the period of time from device
discovery to driver binding is long enough (because there's so much
other activity during bootup) that the device can autosuspend before
the driver is there to prevent it.

For well-behaved devices this wouldn't matter. But unfortunately there
are lots of devices which break when they suspend. That's why
level = auto is not the default.

Alan Stern