Re: [PATCH v2 0/3] Input/HID: joydev fixes for motion sensors
From: Bastien Nocera <hadess@hadess.net>
Date: 2017-08-23 09:12:41
On Thu, 2017-08-17 at 19:01 -0700, Roderick Colenbrander wrote:
From: Roderick Colenbrander <roderick.colenbrander@sony.com>
<snip>
The earlier version of this patch set, added a filter to joydev to ignore devices which have INPUT_PROP_ACCELEROMETER set. Dmitry pointed out that often you could use a motion sensor device as a joystick. He felt the issue is with composite devices. The discussion didn't result in a conclusion. This patch set only filters out motion sensors if they are part of a composite device. Since there is no way during driver initialization to determine whether we are dealing with a composite device, we introduce a new property INPUT_PROP_COMPOSITE to determine this. I think having such flag is beneficial for userspace as well, since applications now get a hint that a device is part of a composite device without having to infer this from a EVIOCGPHYS / EVIOCGUINIQ match across devices. Hopefully this patches will be accepted for 4.14, but maybe earlier if still possible as the next wave of distributions will likely be on 4.13 with more users dealing with this issue.
FWIW, in iio-sensor-proxy, we'd probably be more interested in knowing that the accelerometer is external to the machine, inside an external device, than to know it's part of a "multi-device device", as most sensors already are part of blocks containing other sensors such as gyro, compass, etc.