Hi Luiz,
On 1/2/24 19:39, Luiz Augusto von Dentz wrote:
Hi Jonas,
On Tue, Jan 2, 2024 at 1:19 PM Jonas Dreßler <verdre@xxxxxxx> wrote:
In theory the firmware is supposed to power off the bluetooth card
when we use rfkill to block it. This doesn't work on a lot of laptops
though, leading to weird issues after turning off bluetooth, like the
connection timing out on the peripherals which were connected, and
bluetooth not connecting properly when the adapter is turned on again
quickly after rfkilling.
This series hooks into the rfkill driver from the bluetooth subsystem
to send a HCI_POWER_OFF command to the adapter before actually submitting
the rfkill to the firmware and killing the HCI connection.
---
v1 -> v2: Fixed commit message title to make CI happy
Jonas Dreßler (4):
Bluetooth: Remove HCI_POWER_OFF_TIMEOUT
Bluetooth: mgmt: Remove leftover queuing of power_off work
Bluetooth: Add new state HCI_POWERING_DOWN
Bluetooth: Queue a HCI power-off command before rfkilling adapters
Apart from the assumption of RFKILL actually killing the RF
immediately or not, I'm fine with these changes, that said it would be
great if we can have some proper way to test the behavior of rfkill,
perhaps via mgmt-tester, since it should behave like the
MGMT_OP_SET_POWERED.
Testing this sounds like a good idea, I guess we'd have to teach
mgmt-tester to write to rfkill. The bigger problem seems to be that
there's no MGMT event for power changes and also no MGMT_OP_GET_POWERED,
so that's a bit concerning, could userspace even be notified about
changes to adapter power?
Another thing I'm thinking about now is that queuing the HCI command
using hci_cmd_sync_queue() might not be enough: The command is still
executed async in a thread, and we won't actually block until it has
been sent, so this might be introducing a race (rfkill could kill the
adapter before we actually send the HCI command). The proper way might
be to use a completion and wait until the
set_powered_off_sync_complete() callback is invoked?
include/net/bluetooth/hci.h | 2 +-
net/bluetooth/hci_core.c | 33 ++++++++++++++++++++++++++++++---
net/bluetooth/hci_sync.c | 16 +++++++++++-----
net/bluetooth/mgmt.c | 30 ++++++++++++++----------------
4 files changed, 56 insertions(+), 25 deletions(-)
--
2.43.0
Cheers,
Jonas
