Return-Path: <cyrus@holtmann.org>
Subject: Re: [PATCH] Wait for child devices to go away before deleting a
 connection
From: Marcel Holtmann <marcel@holtmann.org>
To: Brian Rogers <brian@xyzw.org>
Cc: linux-bluetooth@vger.kernel.org,
	Kay Sievers <kay.sievers@vrfy.org>,
	David Woodhouse <dwmw2@infradead.org>
In-Reply-To: <4A711294.5010901@xyzw.org>
References: <4A6424D8.3040306@xyzw.org> <1248077430.4549.97.camel@violet>
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	 <4A70CF45.1060706@xyzw.org> <1248921191.28545.251.camel@violet>
	 <4A711294.5010901@xyzw.org>
Content-Type: text/plain
Date: Thu, 30 Jul 2009 05:49:12 +0200
Message-Id: <1248925752.28545.260.camel@violet>
Mime-Version: 1.0
Sender: linux-bluetooth-owner@vger.kernel.org
List-ID: <linux-bluetooth.vger.kernel.org>

Hi Brian,

> >>>>> Kay, David, wouldn't be pinning of the parent device here be enough to
> >>>>> get this done in a clean way?
> >>>>>   
> >>>>>       
> >>>>>           
> >>>> If there's a way that the connection can be pinned until the child 
> >>>> devices go away, that definitely sounds cleaner to me.
> >>>>     
> >>>>         
> >>> so I pushed some patches to bluetooth-testing tree that should fix this
> >>> problem. They are not fully tested by me. Please test and report back
> >>> the results.
> >>>   
> >>>       
> >> Fails to compile if CONFIG_USB_HIDDEV=y :
> >>
> >> ERROR: "hiddev_disconnect" [net/bluetooth/hidp/hidp.ko] undefined!
> >>
> >> Ironically, the reference to hiddev_disconnect is fine if hiddev isn't 
> >> enabled because then hiddev.h supplies an empty static inline function.
> >>
> >> I'm going to test with a kernel without hiddev for now.
> >>     
> >
> > just take that piece out of the patch. It is not important. I just wanna
> > now if the uevents are now coming in order.
> >   
> 
> I just tried it without hiddev and observed that the input devices go 
> away, but the connection never gets deleted. Then when I turn my mouse 
> back on, bad stuff happens:

I do have a typo here :(

	void hci_conn_hold_device(struct hci_conn *conn)
	{
	        hci_conn_hold(conn);

	        atomic_inc(&conn->devref);
	}
	EXPORT_SYMBOL(hci_conn_hold_device);

	void hci_conn_put_device(struct hci_conn *conn)
	{
	        if (atomic_dec_and_test(&conn->refcnt))
        	        hci_conn_del_sysfs(conn);

        	hci_conn_put(conn);
	}
	EXPORT_SYMBOL(hci_conn_put_device);

The atomic_dec_and_test() should operate on conn->devref. Can you change
that and try again.

Also if that doesn't help, remove the hci_conn_hold() and hci_conn_put()
from the two functions above and try again.

Regards

Marcel