On Thu, 4 Jun 2020 21:28:50 -0700 Abhishek Pandit-Subedi wrote:
> It is preferable to allow suspend even when Bluetooth has problems
> preparing for sleep. When Bluetooth fails to finish preparing for
> suspend, log the error and allow the suspend notifier to continue
> instead.
>
> To also make it clearer why suspend failed, change bt_dev_dbg to
> bt_dev_err when handling the suspend timeout.
>
> Fixes: dd522a7429b07e ("Bluetooth: Handle LE devices during suspend")
> Reported-by: Len Brown <len.brown@xxxxxxxxx>
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
> ---
> To verify this is properly working, I added an additional change to
> hci_suspend_wait_event to always return -16. This validates that suspend
> continues even when an error has occurred during the suspend
> preparation.
>
> Example on Chromebook:
> [ 55.834524] PM: Syncing filesystems ... done.
> [ 55.841930] PM: Preparing system for sleep (s2idle)
> [ 55.940492] Bluetooth: hci_core.c:hci_suspend_notifier() hci0: Suspend notifier action (3) failed: -16
> [ 55.940497] Freezing user space processes ... (elapsed 0.001 seconds) done.
> [ 55.941692] OOM killer disabled.
> [ 55.941693] Freezing remaining freezable tasks ... (elapsed 0.000 seconds) done.
> [ 55.942632] PM: Suspending system (s2idle)
>
> I ran this through a suspend_stress_test in the following scenarios:
> * Peer classic device connected: 50+ suspends
> * No devices connected: 100 suspends
> * With the above test case returning -EBUSY: 50 suspends
>
> I also ran this through our automated testing for suspend and wake on
> BT from suspend continues to work.
>
>
> Changes in v2:
> - Added fixes and reported-by tags
Building W=1 C=1 gcc-10:
In file included from ../net/bluetooth/hci_core.c:38:
../net/bluetooth/hci_core.c: In function ‘hci_suspend_notifier’:
../include/net/bluetooth/bluetooth.h:182:9: warning: format ‘%x’ expects argument of type ‘unsigned int’, but argument 3 has type ‘long unsigned int’ [-Wformat=]
182 | BT_ERR("%s: " fmt, (hdev)->name, ##__VA_ARGS__)
| ^~~~~~
../include/net/bluetooth/bluetooth.h:169:33: note: in definition of macro ‘BT_ERR’
169 | #define BT_ERR(fmt, ...) bt_err(fmt "\n", ##__VA_ARGS__)
| ^~~
../net/bluetooth/hci_core.c:3368:3: note: in expansion of macro ‘bt_dev_err’
3368 | bt_dev_err(hdev, "Suspend notifier action (%x) failed: %d",
| ^~~~~~~~~~
