On Fri, 10 Jul 2020, Darren Hart wrote:

quoted

Some devices, particularly the 3DConnexion Spacemouse wireless 3D
controllers, return more than just the battery capacity in the battery
report. The Spacemouse devices return an additional byte with a device
specific field. However, hidinput_query_battery_capacity() only
requests a 2 byte transfer.

When a spacemouse is connected via USB (direct wire, no wireless dongle)
and it returns a 3 byte report instead of the assumed 2 byte battery
report the larger transfer confuses and frightens the USB subsystem
which chooses to ignore the transfer. Then after 2 seconds assume the
device has stopped responding and reset it. This can be reproduced
easily by using a wired connection with a wireless spacemouse. The
Spacemouse will enter a loop of resetting every 2 seconds which can be
observed in dmesg.

This patch solves the problem by increasing the transfer request to 4
bytes instead of 2. The fix isn't particularly elegant, but it is simple
and safe to backport to stable kernels. A further patch will follow to
more elegantly handle battery reports that contain additional data.

Applied and tested on 5.8.0-rc4+ (aa0c9086b40c) with a 3Dconnexion
SpaceMouse Wireless (tested connected via USB). Observed the same
behavior Grant reports before the patch. After the patch, the device stays
connected successfully.

Tested-by: Darren Hart <dvhart@infradead.org>

Applied, thanks.

-- 
Jiri Kosina
SUSE Labs