[PATCH 0/3] Bluetooth: Power down controller when suspending

[Abhishek Pandit-Subedi]

Hi Marcel and linux-bluetooth,

This patch series adds support for a quirk that will power down the
Bluetooth controller when suspending and power it back up when resuming.

On Marvell SDIO Bluetooth controllers (SD8897 and SD8997), we are seeing
a large number of suspend failures with the following log messages:

[ 4764.773873] Bluetooth: hci_cmd_timeout() hci0 command 0x0c14 tx timeout
[ 4767.777897] Bluetooth: btmrvl_enable_hs() Host sleep enable command failed
[ 4767.777920] Bluetooth: btmrvl_sdio_suspend() HS not actived, suspend failed!
[ 4767.777946] dpm_run_callback(): pm_generic_suspend+0x0/0x48 returns -16
[ 4767.777963] call mmc2:0001:2+ returned -16 after 4882288 usecs

The daily failure rate with this signature is quite significant and
users are likely facing this at least once a day (and some unlucky users
are likely facing it multiple times a day).

Given the severity, we'd like to power off the controller during suspend
so the driver doesn't need to take any action (or block in any way) when
suspending and power on during resume. This will break wake-on-bt for
users but should improve the reliability of suspend.

We don't want to force all users of MVL8897 and MVL8997 to encounter
this behavior if they're not affected (especially users that depend on
Bluetooth for keyboard/mouse input) so the new behavior is enabled via
module param. We are limiting this quirk to only Chromebooks (i.e.
laptop). Chromeboxes will continue to have the old behavior since users
may depend on BT HID to wake and use the system.

These changes were tested in the following ways on a Chromebook running
the 4.19 kernel and a MVL-SD8897 chipset. We added the module param in
/etc/modprobe.d/btmrvl_sdio.conf with the contents
  "options btmrvl_sdio power_down_suspend=Y".

Tests run:

With no devices paired:
- suspend_stress_test --wake_min 10 --suspend_min 10 --count 500

With an LE keyboard paired:
- suspend_stress_test --wake_min 10 --suspend_min 10 --count 500

Using the ChromeOS AVL test suite (stress tests are 25 iterations):
- bluetooth_AdapterSRHealth (basic suite)
- bluetooth_AdapterSRHealth.sr_reconnect_classic_hid_stress
- bluetooth_AdapterSRHealth.sr_reconnect_le_hid_stress

Thanks,
Abhishek


Abhishek Pandit-Subedi (3):
  Bluetooth: Rename and move clean_up_hci_state
  Bluetooth: Add quirk to power down on suspend
  Bluetooth: btmrvl_sdio: Power down when suspending

 drivers/bluetooth/btmrvl_sdio.c  | 10 ++++
 include/net/bluetooth/hci.h      |  7 +++
 include/net/bluetooth/hci_core.h |  6 +++
 net/bluetooth/hci_core.c         | 93 +++++++++++++++++++++++++++++++-
 net/bluetooth/hci_request.c      | 26 ++++++++-
 net/bluetooth/mgmt.c             | 46 +---------------
 6 files changed, 140 insertions(+), 48 deletions(-)

-- 
2.29.2.299.gdc1121823c-goog