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fix(monitorusb): replace hwinfo --usb with sysfs reading to eliminate ioctl audio stutter (PMS 381051) - #969

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fix(monitorusb): replace hwinfo --usb with sysfs reading to eliminate ioctl audio stutter (PMS 381051)#969
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@GongHeng2017 GongHeng2017 commented Nov 10, 2026 •
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问题描述 (PMS 381051)

在受影响的 xHCI 控制器上，USB 设备热插拔时会导致约 970ms 的音频卡顿。

根因分析

MonitorUsb::monitor() 在检测到 USB add/remove 事件时，同步执行 hwinfo --usb。hwinfo 会打开所有 /dev/bus/usb/*/* 设备节点并发送 ioctl(USBDEVFS_CONTROL) 控制传输来读取设备描述符。这些控制传输在受影响的 xHCI 控制器上会阻塞音频等时传输 (isochronous URB) 约 970ms，超过 PulseAudio 约 93ms 的缓冲区，导致可听见的音频卡顿。

修复方案（方案 3）

用直接读取 /sys/bus/usb/devices/ 下的 sysfs 属性文件替代 hwinfo --usb 外部进程。sysfs 文件读取不涉及任何 USB I/O，从根本上消除了控制传输干扰。

修改内容

文件: deepin-devicemanager-server/deepin-deviceinfo/src/hotplug/monitorusb.cpp

  1. 新增 getUsbInfoFromSysfs() 静态函数，遍历 /sys/bus/usb/devices/ 下的设备条目，读取 sysfs 属性（idVendor、idProduct、manufacturer、product、serial、bDeviceClass、bInterfaceClass 等），生成与 hwinfo --usb 输出格式兼容的字符串。

  2. 新增 usbHardwareClass() 辅助函数，根据 bDeviceClass (0x09=hub) 和 HID 接口的 bInterfaceSubClass/bInterfaceProtocol 推导 hwinfo 风格的 "Hardware Class"（hub/keyboard/mouse/usb）。

  3. 新增 readSysfsAttr() 辅助函数，安全读取 sysfs 属性文件。

  4. 在 monitor() 中将 QProcess::execute("hwinfo", {"--usb"}) 替换为 getUsbInfoFromSysfs() 调用。

兼容性保证

生成的字符串格式完全兼容现有消费者：

  • EnableUtils::disableOutDevice(): 需要 "Vendor"(含0x)、"Device"(含0x)、"SysFS Device Link"/"SysFS ID" 用于哈希唯一标识；"Hardware Class" != "hub" 且存在 "SysFS BusID" 用于过滤
  • WakeupUtils::updateWakeupDeviceInfo(): 需要 "Hardware Class" == "keyboard"/"mouse"、"SysFS ID" 用于 wakeup 路径

所有设备块均超过 10 行（满足 LEAST_NUM=10 要求）。

影响范围

  • 仅修改 monitorusb.cpp 一个文件
  • 不改变任何对外接口
  • 不影响 detectthread.cpp 中的 hwinfo --usb --keyboard --mouse 调用（属设计缺陷，不在本次修复范围）
  • 不影响 mainjob.cpp 中的 sqlCopytoKernel 调用（仅在启动和唤醒时执行，非热插拔路径）

Summary by Sourcery

Eliminate USB hotplug audio stutter by switching device information collection from hwinfo to non-I/O sysfs reads.

Bug Fixes:

  • Replace hotplug-time hwinfo USB probing with sysfs-based enumeration to prevent USB control transfers from stalling audio playback.

Enhancements:

  • Preserve downstream USB device, HID, hub, and network adapter metadata consumers by generating compatible device information from sysfs.

@GongHeng2017
fix(monitorusb): replace hwinfo --usb with sysfs reading to eliminate…
72e2d3e 
… ioctl audio stutter

Root cause (PMS 381051): On USB hot-plug events, MonitorUsb::monitor()
spawned "hwinfo --usb" which opens every /dev/bus/usb/*/* node and issues
ioctl(USBDEVFS_CONTROL) control transfers to read device descriptors.  On
affected xHCI controllers these control transfers stall isochronous audio
URBs for ~970 ms, exceeding the ~93 ms PulseAudio buffer and causing
audible playback stuttering.

Fix: Replace the external hwinfo process with direct reads of
/sys/bus/usb/devices/ attribute files (idVendor, idProduct, bDeviceClass,
bInterfaceClass, etc.).  Sysfs reads perform no USB I/O whatsoever,
eliminating the control-transfer interference while producing a string in
the same key:value format that EnableUtils::disableOutDevice() and
WakeupUtils::updateWakeupDeviceInfo() already parse.

The new getUsbInfoFromSysfs() function:
- Enumerates device entries (skipping interfaces) under
  /sys/bus/usb/devices/
- Reads standard sysfs USB attributes (idVendor, idProduct, manufacturer,
  product, serial, bcdDevice, bDeviceClass/SubClass/Protocol, busnum,
  devnum, speed)
- Derives hwinfo-compatible "Hardware Class" from bDeviceClass (hub) and
  HID interface class/subclass/protocol (keyboard/mouse)
- Constructs SysFS Device Link and SysFS ID paths from canonical paths
- Detects USB network adapters for Permanent HW Address / Device File
- Builds Module Alias from device attributes
- Emits >10 lines per device block (required by getMapInfo LEAST_NUM=10)
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deepin-ci-robot commented Nov 10, 2026

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Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

@deepin-ci-robot

deepin-ci-robot commented Nov 10, 2026

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: GongHeng2017

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sourcery-ai Bot commented Nov 10, 2026

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Reviewer's Guide

Implementation

Replace the hotplug-time hwinfo process with sysfs enumeration, including its helpers and required includes, to avoid USB control transfers while preserving the information consumed downstream.

  • deepin-devicemanager-server/deepin-deviceinfo/src/hotplug/monitorusb.cpp L12-181, L250-255 (+2 small edits)
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@GongHeng2017 GongHeng2017 mentioned this pull request Nov 11, 2026
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@GongHeng2017

GongHeng2017 commented Nov 11, 2026

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关闭此 PR：前次修复过于保守（仅修改 monitorusb.cpp 一处 sysfs 替换），未覆盖卡顿核心原因。按负责人纠偏（corr-01a1c449-2）提供的已验证补丁，改由新 PR #971（含 detectthread/monitorusb/threadpool/deviceinfomanager/threadpooltask/mainjob 全链路修改）与 deepin-music 配套 PR #866 共同替代。

Bug: https://pms.uniontech.com/bug-view-381051.html

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