Re: [PATCH V2] input: Fix USB autosuspend on bcm5974

Am Montag, 10. Oktober 2011, 16:38:02 schrieb Matthew Garrett:

On Mon, Oct 10, 2011 at 04:34:38PM +0200, Oliver Neukum wrote:

quoted

Am Montag, 10. Oktober 2011, 16:16:35 schrieb Matthew Garrett:

quoted

On Mon, Oct 10, 2011 at 04:06:37PM +0200, Oliver Neukum wrote:

quoted

This is odd, because the hardware shouldn't generate remote wakeups unless you
request them, like this (usbhid)

I thought needs_remote_wakeup was a hint to the kernel that remote 
wakeup ability was required for the hardware to autosuspend? In theory I

It fulfills that role, but it is not its sole function.

quoted

guess it should be set, but in practice all the hardware supported by 
this driver generates them so it'd be a noop. No objection to adding it 
in the name of correctness (or if some future version is broken, I 
guess...), though.

It is used in usb_port_suspend in form of do_remote_wakeup which
is computed from it. And we send a real control message.

do_remote_wakeup will be set if device_may_wakeup is true, regardless of 
whether the driver asks for it. Or am I misreading choose_wakeup()?

Indeed things have changed. Arguably this raises power consumption.
Anyway, you ought to set it so usbcore will refuse should remote wakeup
fail to be enabled.

	Regards
		Oliver