Messages in this thread | | | Date | Sun, 18 Dec 2005 22:11:07 -0500 (EST) | From | Alan Stern <> | Subject | Re: USB rejecting sleep |
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On Mon, 19 Dec 2005, Benjamin Herrenschmidt wrote:
> Ok, I did a bit more tests here with a Keyspan adapter on my laptop > (well known driver for not having the suspend/resume routines). > > The good thing is with the patch, the machine goes to sleep. However, > the device is not disconnected/reconnected. What happens it that the bus > gets suspended anyway and the driver stays around (possibly getting > errors on some URBs).
Yes, that's what is supposed to happen with that patch.
> This is fine, but not optimal, since that means most of the time that > the device will not work on resume unless disconnected/reconnected. (For > keyspan, it seems that the HW does support the suspend state, thus it's > just a matter of closing/re-opening the port, I suppose it would be easy > enough to fix the driver). > > So this patch is good for it doesn't prevent sleep anymore, but it also > doesn't do what we decided it should do. I think David is right that we > should be able to disconnect the device without actually removing the > device & driver from sysfs, just let that happen at resume time.
Of course the patch doesn't do what we talked about. It says so right in the Changelog comment.
I disagree with the idea of disconnecting the device. The right thing to do is what David wanted all along: unbind the driver. This would require only a small change to the driver core.
It's too late for me to work on this now, but maybe tomorrow I'll have to a chance to write something.
Alan Stern
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