Re: [RFC PATCH v5 0/5] Bluetooth: Handle system suspend gracefully - Abhishek Pandit-Subedi

From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
To: Marcel Holtmann <marcel@holtmann.org>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
	Alain Michaud <alainm@chromium.org>,
	Bluez mailing list <linux-bluetooth@vger.kernel.org>,
	ChromeOS Bluetooth Upstreaming
	<chromeos-bluetooth-upstreaming@chromium.org>,
	"David S. Miller" <davem@davemloft.net>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Jakub Kicinski <kuba@kernel.org>
Subject: Re: [RFC PATCH v5 0/5] Bluetooth: Handle system suspend gracefully
Date: Wed, 11 Mar 2020 08:41:08 -0700	[thread overview]
Message-ID: <CANFp7mVQyzwb1MnDjid9TSBb_15OmyJ85doZQNpyd-2J-SAN3w@mail.gmail.com> (raw)
In-Reply-To: <C9E912BC-01E0-4E5D-ABC9-DBA932231E50@holtmann.org>

Sure -- patch incoming in a few minutes.

On Wed, Mar 11, 2020 at 8:03 AM Marcel Holtmann <marcel@holtmann.org> wrote:
>
> Hi Abhishek,
>
> > This patch series prepares the Bluetooth controller for system suspend
> > by disconnecting all devices and preparing the event filter and LE
> > whitelist with devices that can wake the system from suspend.
> >
> > The main motivation for doing this is so we can enable Bluetooth as
> > a wake up source during suspend without it being noisy. Bluetooth should
> > wake the system when a HID device receives user input but otherwise not
> > send any events to the host.
> >
> > This patch series was tested on several Chromebooks with both btusb and
> > hci_serdev on kernel 4.19. The set of tests was basically the following:
> > * Reconnects after suspend succeed
> > * HID devices can wake the system from suspend (needs some related bluez
> >  changes to call the Set Wake Capable management command)
> > * System properly pauses and unpauses discovery + advertising around
> >  suspend
> > * System does not wake from any events from non wakeable devices
> >
> > Series 2 has refactored the change into multiple smaller commits as
> > requested. I tried to simplify some of the whitelist filtering edge
> > cases but unfortunately it remains quite complex.
> >
> > Series 3 has refactored it further and should have resolved the
> > whitelisting complexity in series 2.
> >
> > Series 4 adds a fix to check for powered down and powering down adapters.
> >
> > Series 5 moves set_wake_capable to the last patch in the series and
> > changes BT_DBG to bt_dev_dbg.
> >
> > Please review and provide any feedback.
>
> so I was planning to apply patches 1-4. The only thing that I noticed was that patch 2 introduces the following warning.
>
>   CC      net/bluetooth/hci_request.o
> net/bluetooth/hci_request.c: In function ‘hci_req_prepare_suspend’:
> net/bluetooth/hci_request.c:973:6: warning: unused variable ‘old_state’ [-Wunused-variable]
>   973 |  int old_state;
>       |      ^~~~~~~~~
>
> I think this variable should only be introduced in patch 4. Are you able to respin this series so that the variable moves to patch 4. If not, I can try to fix this myself.
>
> Regards
>
> Marcel
>