Bug#992637: Dropped packets/high latency on USB bus when using USB oscilloscope in bullseye
Package: linux-image-amd64
Version: 5.10.46-4
Severity: important
X-Debbugs-Cc: v.schoor.kobus@gmail.com
Dear Maintainer,
* What led up to the situation?
After installing bullseye, a specialized piece of hardware that I use
(Hantek 6022BE oscilloscope) has stopped transmitting packets reliably
over USB. This tool is used to read voltages from electronic circuits
in realtime - if there is significant latency or some packets are
dropped the signal becomes distorted and unusable. However, after
working with the maintainer of the software that I use to interact with
the scope (OpenHantek, see GitHub issue
here: https://github.com/OpenHantek/OpenHantek6022/issues/207) it seems
that the issue is specific to my laptop/USB bus. The maintainer
confirmed that if there was significant latency, or if packets were
dropped, the issue would present itself like I'm seeing it.
The same issue is present on Fedora Workstation 34 on my laptop.
* What exactly did you do (or not do) that was effective (or
ineffective)?
I've tried various things that didn't help:
- I tried someone else's exact same scope, the same issue occurred (so
the issue is on my laptop)
- I tried the realtime version of the kernel
- I tried all the ports on my laptop, which included USB 2 and 3 ports
Some things that I've noticed:
- My battery lasts significantly longer after upgrading to bullseye
(around 2 hours extra I would guess). I'm not sure if there is now
extra power saving features present in the kernel which might be
interfering with my USB bus. The issue is present both when connected
to AC or when running on battery
- The issue doesn't immediately occur. The device works ok for around
10 seconds before the signal becomes corrupted
- All my other USB devices still seem to work fine (mouse, external
HDD)
Installing buster's latest kernel on bullseye (I added the buster repos
and pinned it, and installed linux-image-4.19.0-17-amd64 from the
oldstable repos) resolves the problem, so it has something to do with
the kernel. Other people have reported that they are not experiencing
the issue on their side, even with the new kernel (however they have
different hardware than me).
I am not seeing any error messages in dmesg, so I presume the kernel is
not aware of the issue.
The oscilloscope’s USB controller is a Cypress CY7C68013A-100AXC (as I
understand it, a EX USB FX2 chip).
My laptop is an HP Probook 450 G5. lspci gives the following output:
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v6/7th Gen Core
Processor Host Bridge/DRAM Registers (rev 08)
00:02.0 VGA compatible controller: Intel Corporation UHD Graphics 620
(rev 07)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200
v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 08)
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI
Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-
LP Thermal subsystem (rev 21)
00:15.0 Signal processing controller: Intel Corporation Sunrise Point-
LP Serial IO I2C Controller #0 (rev 21)
00:15.1 Signal processing controller: Intel Corporation Sunrise Point-
LP Serial IO I2C Controller #1 (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP
CSME HECI #1 (rev 21)
00:17.0 SATA controller: Intel Corporation Sunrise Point-LP SATA
Controller [AHCI mode] (rev 21)
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root
Port #5 (rev f1)
00:1c.5 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root
Port #6 (rev f1)
00:1d.0 PCI bridge: Intel Corporation Device 9d1b (rev f1)
00:1f.0 ISA bridge: Intel Corporation Sunrise Point LPC Controller/eSPI
Controller (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev
21)
00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev
21)
00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21)
01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
02:00.0 Network controller: Intel Corporation Wireless 8265 / 8275 (rev
78)
03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd.
RTS522A PCI Express Card Reader (rev 01)
Please let me know if I can give any more information.
-- System Information:
Debian Release: 11.0
APT prefers stable-security
APT policy: (500, 'stable-security'), (500, 'stable'), (1,
'oldstable-updates'), (1, 'oldstable')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-8-amd64 (SMP w/8 CPU threads)
Locale: LANG=en_ZA.UTF-8, LC_CTYPE=en_ZA.UTF-8 (charmap=UTF-8),
LANGUAGE=en_ZA:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages linux-image-amd64 depends on:
ii linux-image-5.10.0-8-amd64 5.10.46-4
linux-image-amd64 recommends no packages.
linux-image-amd64 suggests no packages.
-- no debconf information
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