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. Signed-off-by: Grant Likely <[email protected]> Cc: Darren Hart <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Benjamin Tissoires <[email protected]> Cc: [email protected] --- drivers/hid/hid-input.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index dea9cc65bf80..e8641ce677e4 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -350,13 +350,13 @@ static int hidinput_query_battery_capacity(struct hid_device *dev) u8 *buf; int ret; - buf = kmalloc(2, GFP_KERNEL); + buf = kmalloc(4, GFP_KERNEL); if (!buf) return -ENOMEM; - ret = hid_hw_raw_request(dev, dev->battery_report_id, buf, 2, + ret = hid_hw_raw_request(dev, dev->battery_report_id, buf, 4, dev->battery_report_type, HID_REQ_GET_REPORT); - if (ret != 2) { + if (ret < 2) { kfree(buf); return -ENODATA; } -- 2.20.1
