RE: [PATCH v5 1/2] Bluetooth: btmrvl: add setup handler

Hi Johan,

Hi Bing,
=20
On Tue, Sep 24, 2013, Bing Zhao wrote:

quoted

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that is a bug. It should only be ever called once. Could this be due
to RFKILL issue we had? Please re-test with Johan's patches applied
and check if it makes a difference. Otherwise please send some logs
since we want to get this fixed.

Amitkumar Karwar has tested it with latest code on bluetooth-next tree
but the result is the same.
Apparently two threads race to call hci_dev_open(). If the thread from
hci_sock calls hci_dev_open earlier, it ends up not updating HCI_SETUP
hdev flag in hci_power_on(). This results that the setup handler gets
called again when user brings up the interface later.

=20
Let's see if I understood this right: the only hci_dev_open call in
hci_sock.c is the one for the HCIDEVUP ioctl. So what you're doing is
having user space call the HCIDEVUP ioctl before our own hci_power_on
callback gets called to initialize the adapter?

That's right. The ioctl is initiated by the Bluetooth daemon.
Amitkumar has a setup that can reproduce this corner case easily.
I tested it on my Ubuntu but I couldn't replicate it.

=20
You're right that we're missing the clearing of the HCI_SETUP flag for
such a scenario. Could you try the attached patch. It should fix the
issue. One problem that it does have is that if the HCIDEVUP ioctl path
goes through before hci_power_on gets called we will never notify mgmt
of the adapter. However, that might be acceptable here since if you're
using HCIDEVUP like this it seems it's not a mgmt based system anyway.
=20

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I checked the bluetooth-next tree, the following two patches (by
Johan) are not present in this tree.

bf54303 Bluetooth: Fix rfkill functionality during the HCI setup stage
5e13036 Bluetooth: Introduce a new HCI_RFKILLED flag

They are in bluetooth.git tree. So, I'm not certain if Amitkumar has
applied them manually or not. Anyway we will re-test with Johan's
patches applied and confirm if they fix the race or not.

=20
I don't think these patches will help you in this case.

OK, we will test your patch instead.

Thanks,
Bing