Re: [PATCH 1/2] Revert "Revert "HID: Fix logitech-dj: missing Unifying device issue""

From: Peter Hurley <peter@hurleysoftware.com>
To: Peter Wu <lekensteyn@gmail.com>
Cc: Nestor Lopez Casado <nlopezcasad@logitech.com>,
	jkosina@suse.cz, benjamin.tissoires@gmail.com, adlr@chromium.org,
	joseph.salisbury@canonical.com, linux-input@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Sarah Sharp <sarah.a.sharp@linux.intel.com>,
	linux-usb@vger.kernel.org
Subject: Re: [PATCH 1/2] Revert "Revert "HID: Fix logitech-dj: missing Unifying device issue""
Date: Tue, 13 Aug 2013 08:13:17 -0400	[thread overview]
Message-ID: <520A22DD.3010308@hurleysoftware.com> (raw)
In-Reply-To: <2324751.QaRpZppUQy@al>

On 08/12/2013 05:54 PM, Peter Wu wrote:
> On Thursday 18 July 2013 16:28:01 Peter Hurley wrote:
>> Before we revert to using the workaround, I'd like to suggest that
>> this new "hidden" problem may be an interaction with the xhci_hcd host
>> controller driver only.
>>
>> Looking at the related bug, the OP indicates the machine only has
>> USB3 ports. Additionally, comments #7, #100, and #104 of the original
>> bug report add additional information that would seem to confirm
>> this suspicion.
>>
>> Let me add I have this USB device running on the uhci_hcd driver
>> with or without this workaround on v3.10.
>
> This problem does not seem specific to xhci, uhci seems also effected.

If true, it would certainly help to have a bug report confirming uhci
failure from a bare-metal system which contained:
1) kernel version
2) complete dmesg output
3) lsusb -v output
4) lsmod output
5) usbmon capture from a plug attempt

> Today I
> upgraded a system (running Arch Linux) from kernel 3.9.9 to 3.10.5. After a
> reboot to 3.10.5, things broke. The setup:
>
> - There are two USB receivers plugged into USB 1.1 ports (different buses
> according to lsusb, uhci), each receiver is paired to a K360 keyboard.
> - One of the receivers are passed to a QEMU guest with -usbdevice host:$busid.
> $devid. This keyboard is working (probably because QEMU performed a reset).
> - Since 3.10.5, the keyboard that is *not* passed to the QEMU guest is not
> functioning on reboot.
>
> After closing the QEMU guest, the USB bus gets reset(?) after which the other
> keyboard suddenly gets detected. I had only booted 3.10.5 twice before rolling
> back to 3.9.9, both boots triggered the issue. Do I need to provide a usbmon,
> lsusb, dmesg and/ or other details from 3.10.5?

Do both keyboards work on bare metal? Seems like this problem might be
specific to qemu (or kvm) and you may get more insight on those lists.

> Note that there are other Arch Linux users who have reported issues[1][2]

Unfortunately, not even one user in the referenced reports identified
the usb hub the receiver was plugged into.

> since upgrading to 3.10.z. Triggering a re-enumeration by writing the magic
> HID++ message[3] makes the paired devices appear again (as reported in
> forums[1], I haven't tried this on the affected UHCI machine).
>
> While the underlying bug is fixed, can this patch be forwarded to stable? I see
> that 3.10.6 has been released, but still without this patch.

This is still a workaround and not really a fix for the underlying bug.

> Regards,
> Peter
>
>   [1]: https://bbs.archlinux.org/viewtopic.php?id=167210
>   [2]: https://bugs.archlinux.org/task/35991
>   [3]: https://bbs.archlinux.org/viewtopic.php?pid=1309535#p1309535