linux-kernel - Re: bluetooth related firmware loader spew on resume.

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Message-ID: <s5htx1mvyo8.wl-tiwai@suse.de>
Date:	Wed, 26 Nov 2014 15:12:07 +0100
From:	Takashi Iwai <tiwai@...e.de>
To:	Marcel Holtmann <marcel@...tmann.org>
Cc:	Oliver Neukum <oneukum@...e.de>, Dave Jones <davej@...hat.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	pgynther@...gle.com, linux-bluetooth@...r.kernel.org
Subject: Re: bluetooth related firmware loader spew on resume.

At Wed, 26 Nov 2014 23:05:20 +0900,
Marcel Holtmann wrote:
> 
> Hi Oliver,
> 
> >> In order to paper over this, we may also remember the failing firmware
> >> and avoid loading it.  This might be an easer way than the endless
> >> fight against UMH race...
> > 
> > 
> > the full fix would be to implement reset_resume() for btusb.
> > It seems to me that setup() should be split in two methods,
> > one to request the firmware from user space and the second
> > to transfer it to the device. reset_resume() would just need
> > to repeat the second operation.
> 
> so when you do hci_register_dev, then hdev->setup is only called once. I really mean only once per lifetime of the hci_dev. So you would need to unregister the hci_dev first before hdev->setup will ever be called again. So I am not sure this is actually the problem here. The problem here is entirely within request_firmware() unless of course we run through the USB probe handlers again. Which I do not see happening here.
> 
> And we have hdev->setup this way since normally the Bluetooth devices keep their firmware patches and not forget about them and suspend-resume cycles. If the USB device of course jumps of the bus during it then all bets are off anyway.

Usually you can avoid unnecessary rebinding when you provide a proper
reset_resume callback.  I guess that's what Oliver suggested.


Takashi
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