Strange regression in hid_llogitech_dj (was: Re: Linux 5.2-rc4)

[Rafael J. Wysocki]

On Sunday, June 9, 2019 5:46:48 AM CEST Linus Torvalds wrote:
> No, I'm not confused, and I haven't lost track of what day it is, I do
> actually know that it's still Saturday here, not Sunday, and I'm just
> doing rc4 a bit early because I'll be on an airplane during my normal
> release time. And while I've done releases on airports and airplanes
> before, I looked at my empty queue of pull requests and went "let's
> just do it now".
> 
> We've had a fairly calm release so far, and on the whole that seems to
> hold. rc4 isn't smaller than rc3 was (it's a bit bigger), but rc3 was
> fairly small, so the size increase isn't all that worrisome. I do hope
> that we'll start actually shrinking now, though.

I noticed that the cordless mouse used by me with one of the machines here
stopped to work in 5.2-rc (up to and including the -rc4).

Bisection turned up commit 74808f9115ce ("HID: logitech-dj: add support for non
unifying receivers").

Of course, that commit does not revert cleanly from 5.2-rc4, but I have reverted
the changes made by it in hid/hid-ids.h and I took the version of hid/hid-logitech-dj.c
from commit b6aeeddef68d ("HID: logitech-dj: add logi_dj_recv_queue_unknown_work
helper"), which is the parent of commit 74808f9115ce, and that made the mouse
work again for me.

Here's the output of "dmesg | grep -i logitech" from 5.2-rc4 with the above changes:

[    4.288905] usb 1-2: Manufacturer: Logitech
[    5.444621] input: Logitech USB Receiver as /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.0/0003:046D:C52F.0002/input/input23
[    5.446960] hid-generic 0003:046D:C52F.0002: input,hidraw1: USB HID v1.11 Mouse [Logitech USB Receiver] on usb-0000:00:14.0-2/input0
[    5.451265] input: Logitech USB Receiver Consumer Control as /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.1/0003:046D:C52F.0003/input/input24
[    5.507545] hid-generic 0003:046D:C52F.0003: input,hiddev96,hidraw2: USB HID v1.11 Device [Logitech USB Receiver] on usb-0000:00:14.0-2/input1

Please let me know what you need to diagnose this.

Thanks,
Rafael