On 1/3/24 13:15, Jonas Dreßler wrote:
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?
Sent v3 of the patchset now, I didn't add a test to mgmt-tester because
it's actually quite tricky to notice the full shutdown sequence happened
rather than just closing the device. As long as no devices are
connected, the difference is mostly in a few (faily random) events:
btmon without the patch:
@ MGMT Event: Class Of Device Changed (0x0007) plen 3
{0x0001} [hci0] 169.101804
Class: 0x000000
Major class: Miscellaneous
Minor class: 0x00
@ MGMT Event: New Settings (0x0006) plen 4
{0x0001} [hci0] 169.101820
Current settings: 0x00000ac0
Secure Simple Pairing
BR/EDR
Low Energy
Secure Connections
btmon with the patch:
< HCI Command: Write Scan Enable (0x03|0x001a) plen 1
#109 [hci0] 7.031852
Scan enable: No Scans (0x00)
> HCI Event: Command Complete (0x0e) plen 4
#110 [hci0] 7.033026
Write Scan Enable (0x03|0x001a) ncmd 1
Status: Success (0x00)
< HCI Command: LE Set Extended Advertising Enable (0x08|0x0039) plen 2
#111 [hci0] 7.033055
Extended advertising: Disabled (0x00)
Number of sets: Disable all sets (0x00)
> HCI Event: Command Complete (0x0e) plen 4
#112 [hci0] 7.034202
LE Set Extended Advertising Enable (0x08|0x0039) ncmd 1
Status: Success (0x00)
< HCI Command: LE Clear Advertising Sets (0x08|0x003d) plen 0
#113 [hci0] 7.034233
> HCI Event: Command Complete (0x0e) plen 4
#114 [hci0] 7.035527
LE Clear Advertising Sets (0x08|0x003d) ncmd 1
Status: Success (0x00)
@ MGMT Event: Class Of Device Changed (0x0007) plen 3
{0x0001} [hci0] 7.035554
Class: 0x000000
Major class: Miscellaneous
Minor class: 0x00
@ MGMT Event: New Settings (0x0006) plen 4
{0x0001} [hci0] 7.035568
Current settings: 0x00000ac0
Secure Simple Pairing
BR/EDR
Low Energy
Secure Connections
Maybe we could add a fake connection and check whether that is
disconnected on the rfkill, but I don't think mgmt-tester supports that..
Fwiw, I don't think having a test for this is super important, this is a
regression a lot of people would notice very quickly I think.
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
Cheers,
Jonas
