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Subject: Re: Temporary device removal during discovery
From:   Bastien Nocera <hadess@hadess.net>
To:     Andrey Batyiev <batyiev@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc:     linux-bluetooth <linux-bluetooth@vger.kernel.org>
Date:   Thu, 09 Jul 2020 10:26:06 +0200
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On Thu, 2020-07-09 at 01:57 +0300, Andrey Batyiev wrote:
> Hi Luiz,
> 
> On Thu, Jul 9, 2020 at 12:14 AM Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
> > The delta logic might be a nice addition as a separate patch, it is
> > more for detecting devices disappearing then actually cleanup
> > during
> > power off.
> No-no, it's not about adapter powering off.
> 
> I meant that (external) devices never disappear from the bluez device
> list during the discovery,
> even if the (external) devices are turned off (i.e. they should be
> purged by bluez).
> 
> So:
> - bluez is central
> - bluez is discovering
> - peripheral appear for a moment, than disappear (i.e. peripheral
> would be turned off)
> - bluez would not remove device from the list (at least until
> discovery is stopped)
> 
> Use case:
> - bluez is monitoring environment (discovering literally forever)
> - peripherals are brought in and out of bluez visibility range
> - bluez list of visible devices grows infinitely and causes problems
> (hundreds of devices)

I'd also expect devices that are recently discovered to disappear if
they haven't replied to a discovery in 30 seconds. It would stop
GNOME's Bluetooth Settings's Bluetooth list forever expanding.

Or we need to give the ability for front-ends to do that by exporting
the "last seen" dates.

Cheers