The hid-nintendo driver has been plagued by an issue where rumble command traffic to bluetooth-connected controllers can cause frequent power downs of the controllers. Digging into other pro controller driver implementations, I've not found anything that hid-nintendo is doing incorrectly. Some implementations seem to be working around the same problem (e.g. libsdl's hidapi implementation rate limits rumble commands to avoid the problem). hid-nintendo already rate limits rumble control packets, but that does not solve the problem. Using btmon output, I've fuond the the disconnections reliably occur shortly after the controller's reporting rate become erratic. The controller is meant to report input packets roughly every 15ms. Sending rumble commands can sometimes result in the input packets arriving in bursts/batches. Once the controller and/or BT stack enters this state, even halting rumble commands will never allow the reporting rate to recover to nominal. The controller will eventually disconnect. This patch set strives to avoid the problematic scenario. It detects if input reports arrive at clearly incorrect deltas. During these times, the driver will hold off on transmitting any rumble commands to the controller. This approach has allowed the reporting rate to reliably recover in my testing. I've not been able to generate a controller disconnection during hours of testing games with frequent rumble. The behavior of this mechanism is tunable using #defines. We may need to tweak/tune as the mitigation is used on different hardware setups. My suspicion is that the core issue is somewhere in the bluez stack. My next step is to investigate that lead in more detail. This patchset at least allows for use of the controllers via bluetooth with rumble enabled without frequently disconnecting. Daniel J. Ogorchock (2): HID: nintendo: prevent rumble queue overruns HID: nintendo: fix rumble rate limiter drivers/hid/hid-nintendo.c | 95 ++++++++++++++++++++++++++++++++++---- 1 file changed, 86 insertions(+), 9 deletions(-) -- 2.39.1
