快速定位终端侧摄像头黑屏故障的USB设备枚举重置技巧

# 1.1 确认设备是否挂载到总线树
lsusb -t  # 关注 "If#" 列是否绑定 uvcvideo 驱动，若显示 "(none)" 则探测失败

# 1.2 深度解析描述符（关键：bMaxPacketSize0, bConfigurationValue, Interface Class 0x0E）
lsusb -v -d <VID>:<PID> 2>/dev/null | grep -A 20 "Device Descriptor|Configuration|Interface"

# 2.1 挂载 usbmon (内核需开启 CONFIG_USB_MON)
mount -t debugfs none /sys/kernel/debug
# 2.2 确定总线编号 (对应 lsusb -t 输出的 Bus ID)
cat /sys/kernel/debug/usb/usbmon/0u  # 0u 代表所有总线，或指定 1u, 2u
# 2.3 后台抓包并触发故障复现 (如拔插/重置)
cat /sys/kernel/debug/usb/usbmon/1u > /tmp/enum_trace.log &
# 2.4 使用 Wireshark 离线分析 (File -> Open -> USB PCAP)

# 触发 uvcvideo 驱动的 disconnect -> probe 流程
echo -n "1-1.2:1.0" > /sys/bus/usb/drivers/uvcvideo/unbind
sleep 1
echo -n "1-1.2:1.0" > /sys/bus/usb/drivers/uvcvideo/bind
# 或针对整个设备 (需确认无其他接口被占用)
echo -n "1-1.2" > /sys/bus/usb/drivers/usb/unbind
echo -n "1-1.2" > /sys/bus/usb/drivers/usb/bind

// 在 uvc_driver 或自定义探测函数中主动触发
usb_lock_device(udev);
usb_reset_device(udev); // 发送 Set Feature (DEVICE_REMOTE_WAKEUP) + Set Configuration
usb_unlock_device(udev);

# 通过 sysfs 对 Hub 下游端口发起暂停/恢复周期 (模拟物理拔插电信号)
echo 0 > /sys/bus/usb/devices/1-1.2/authorized  # 禁用设备 (触发 disconnect)
sleep 2
echo 1 > /sys/bus/usb/devices/1-1.2/authorized  # 重新授权 (触发枚举)

# 需 Hub 支持 Port Power Switching (LPS/个别端口供电控制)
echo 0 > /sys/bus/usb/devices/1-1/power/port_power  # 切断下游端口 VBUS
sleep 3  # 关键：需大于设备电容放电时间 (建议 ≥ 2s)
echo 1 > /sys/bus/usb/devices/1-1/power/port_power  # 恢复供电

# 1. 确认当前电源管理策略
cat /sys/bus/usb/devices/1-1.2/power/control  # 输出 "auto" 表示开启自动挂起
cat /sys/bus/usb/devices/1-1.2/power/autosuspend_delay_ms

# 2. 临时禁用验证 (若禁用后故障消失，锁定为 PM 竞态)
echo on > /sys/bus/usb/devices/1-1.2/power/control

# 3. 內核参数永久禁用 (针对特定 VID/PID)
# /etc/modprobe.d/usb-pm.conf
options usbcore autosuspend=-1  # 全局禁用 (影响功耗，慎用)
# 或更精准的 udev 规则 (/etc/udev/rules.d/99-camera-pm.rules)
ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="xxxx", ATTR{idProduct}=="yyyy", ATTR{power/control}="on"

[Systemd Service: usb-cam-guardian]
       |
       +---> [Monitor Thread] : 轮询 /sys/bus/usb/devices/*/power/level, uvcvideo 错误计数器
       |         |
       |         +---> 触发阈值判定 (连续 3 次 -EPIPE / 设备节点消失 / 视频流帧率 < 1fps)
       |
       +---> [Recovery Executor] : 策略引擎
       |         |
       |         +---> Level 1: uvcvideo rebind (无感)
       |         +---> Level 2: Hub Port Reset (秒级中断)
       |         +---> Level 3: Port Power Cycle (分钟级中断, 需上报运维)
       |
       +---> [Telemetry Reporter] : 结构化日志写入 journald / 上报云端 (JSON 格式)
             { "ts": "", "sn": "", "bus": "", "level": "", "action": "", "result": "", "dmesg_snippet": "" }

# 伪代码：分级恢复决策树
def recover_device(dev_path, failure_count):
    if failure_count <= 2:
        return rebind_driver(dev_path)          # Level 1
    elif failure_count <= 5:
        return hub_port_reset(dev_path)         # Level 2
    else:
        if confirm_no_critical_siblings(dev_path):
            return port_power_cycle(dev_path)   # Level 3
        else:
            alert_manual_intervention(dev_path) # 保护同 Hub 关键设备
            return False

# 1. 找到 xHCI 控制器 MMIO 基址
lspci -vv -d *:*:* | grep -A 20 "XHCI" | grep "Memory at"
# 假设基址 0xfe200000

# 2. 读取 Port Status & Control (PORTSC) 与 Link Control
# 偏移参考 xHCI Spec 5.4.8 / 5.4.9
devmem 0xfe200000 32  # CAPLENGTH/HCIVERSION
# 遍历端口偏移 (0x440 + n*0x10) 读取 PORTSC
# 关键位: PORTSC.PLS (Port Link State), PORTSC.PED (Port Enabled/Disabled)
# 关键位: PORTLI (Link Info) - 记录协商后的预加重/均衡索引

// 固件侧关键埋点结构体 (共享内存映射给 Host 工具读取)
typedef struct {
    uint32_t timestamp_us;
    uint8_t  event_id;        // EV_SET_ADDRESS, EV_LTSSM_CHANGE, EV_EP0_STALL
    uint8_t  ltssm_state;     // 设备端 LTSSM 状态编码
    uint16_t ep0_status;      // EP0 CSR 寄存器快照
    uint32_t phy_status_reg;  // PHY 侧寄存器 (PLL Lock, Signal Detect)
} usb_dbg_event_t;

[物理摄像头] <--USB 3.0 Cable--> [Root Hub (Host OS)]
                                      |
                    +-----------------+-----------------+
                    |                 |                 |
              [Host uvcvideo]   [VFIO-PCI/usbip]   [udev rules]
                    |                 |                 |
              (宿主机驱动)      (透传给 VM)       (透传给 Container)
                    |                 |                 |
              正常工作           枚举正常           **枚举卡住/设备节点消失**

# K8s Device Plugin 配置片段: 资源名为 usb-camera-4k
# 关键：启用 "cdi" (Container Device Interface) 规范，而非传统 device plugin
apiVersion: v1
kind: ConfigMap
metadata:
  name: usb-camera-cdi-config
data:
  # 定义设备规格，包含重置所需的 sysfs 路径
  device.yaml: |
    devices:
    - name: "camera-4k-port-1"
      containerEdits:
        deviceNodes:
        - path: /dev/video10  # 宿主机固定节点 (udev 规则绑定)
          major: 81
          minor: 10
          fileMode: 0660
          gid: 44  # video group
        env:
        - name: USB_SYSFS_PATH
          value: "/sys/bus/usb/devices/1-1.2"  # 宿主机拓扑路径

# test_usb_enum_stress.py (运行于测试治具控制器)
import pytest
import usb.core
import usb.util
import time
import logging

TARGET_VID = 0x1234
TARGET_PID = 0x5678
CYCLES = 10000
MAX_ENUM_TIME_MS = 500

@pytest.fixture(scope="module")
def hub_controller():
    # 控制治具 Hub 端口供电/复位 (GPIO/Relay/USB Hub API)
    return HubController(port=1)

def test_cold_boot_enumeration(hub_controller):
    """冷启动枚举耗时与成功率"""
    for i in range(CYCLES):
        hub_controller.power_cycle(off_delay=3, on_delay=1)  # 物理断电
        start = time.monotonic()
        dev = usb.core.find(idVendor=TARGET_VID, idProduct=TARGET_PID, timeout=2000)
        elapsed = (time.monotonic() - start) * 1000
        
        assert dev is not None, f"Cycle {i}: Device not found after power cycle"
        assert elapsed < MAX_ENUM_TIME_MS, f"Cycle {i}: Enum timeout {elapsed:.1f}ms"
        
        # 校验关键描述符
        assert dev.bMaxPacketSize0 == 512, "USB 3.0 MaxPacketSize0 mismatch"
        cfg = dev.get_active_configuration()
        assert cfg.bNumInterfaces >= 2, "Missing UVC interfaces"
        
        # 记录性能基线
        logging.info(f"Cycle {i}: Enum OK, Time={elapsed:.1f}ms")

def test_selective_suspend_resume_stress(hub_controller):
    """选择性挂起/唤醒 1000 次循环"""
    dev = usb.core.find(idVendor=TARGET_VID, idProduct=TARGET_PID)
    for i in range(1000):
        # 触发 Autosuspend (需内核支持 usbcore.autosuspend=1)
        dev.ctrl_transfer(0x40, 0x00, 0x03, 0, b'')  # 模拟 Set Feature FUNCTION_SUSPEND
        time.sleep(0.5)
        # 强制唤醒
        dev.ctrl_transfer(0x40, 0x00, 0x00, 0, b'')  # 模拟 Clear Feature
        time.sleep(0.2)
        # 验证设备仍响应
        assert dev.ctrl_transfer(0x80, 0x06, 0x0100, 0, 18) is not None

# /etc/udev/rules.d/99-usb-camera-security.rules
# 策略：默认拒绝，显式放行，绑定固定节点，禁止非 root 修改属性

# 1. 默认拒绝所有新增 USB 设备授权
SUBSYSTEM=="usb", ACTION=="add", ATTR{authorized}="0"

# 2. 仅放行认证通过的摄像头 (VID/PID + 序列号双因子)
# 序列号需在量产烧录阶段写入 OTP 区，防克隆
SUBSYSTEM=="usb", ACTION=="add", 
    ATTRS{idVendor}=="1234", ATTRS{idProduct}=="5678", 
    ATTRS{serial}=="CAM-SN-[A-F0-9]{12}", 
    ATTR{authorized}="1", 
    SYMLINK+="camera/approved/%k", 
    GROUP="video", MODE="0660", 
    RUN+="/usr/local/bin/usb-audit-log.sh add $env{DEVPATH} $env{ID_SERIAL_SHORT}"

# 3. 禁止非 root 用户修改 power/control, authorized 等敏感属性
SUBSYSTEM=="usb", ACTION=="add", 
    RUN+="/bin/chmod 640 /sys$env{DEVPATH}/power/control /sys$env{DEVPATH}/authorized", 
    RUN+="/bin/chown root:root /sys$env{DEVPATH}/power/control /sys$env{DEVPATH}/authorized"

# /usr/local/bin/usb-audit-log.sh (由 udev 触发)
#!/bin/bash
ACTION=$1
DEVPATH=$2
SERIAL=$3
TIMESTAMP=$(date --iso-8601=seconds)
HOSTNAME=$(hostname)
# 结构化 JSON 输出，对接 Filebeat/Fluent Bit -> Elasticsearch/Splunk
jq -n --arg ts "$TIMESTAMP" --arg host "$HOSTNAME" --arg act "$ACTION" --arg path "$DEVPATH" --arg sn "$SERIAL" 
  '{timestamp: $ts, host: $host, event: "usb_enumeration", action: $act, devpath: $path, serial: $sn, severity: "info"}' 
  >> /var/log/usb_audit.log

// usb_enum_tracer.bpf.c (使用 libbpf/clang 编译)
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

struct enum_event {
    __u64 timestamp_ns;
    __u32 pid;
    __u16 vid;
    __u16 pid;
    __u8  bus;
    __u8  addr;
    __u8  event_type; // 0=PROBE_START, 1=DESC_READ, 2=SET_ADDR, 3=SET_CFG, 4=RESET, 5=FAIL
    __s32 retval;
    char  comm[TASK_COMM_LEN];
};

struct {
    __uint(type, BPF_MAP_TYPE_RINGBUF);
    __uint(max_entries, 1 << 24);
} events SEC(".maps");

// 1. usb_probe_interface (驱动探测入口)
SEC("kprobe/usb_probe_interface")
int BPF_KPROBE(probe_usb_probe_interface, struct usb_interface *intf, const struct usb_device_id *id) {
    struct enum_event *e = bpf_ringbuf_reserve(&events, sizeof(*e), 0);
    if (!e) return 0;
    e->timestamp_ns = bpf_ktime_get_ns();
    e->pid = bpf_get_current_pid_tgid() >> 32;
    bpf_get_current_comm(&e->comm, sizeof(e->comm));
    e->event_type = 0;
    // 读取设备 VID/PID (需处理指针解引用安全)
    bpf_probe_read_kernel(&e->vid, sizeof(e->vid), &intf->dev.driver->name); // 简化示例
    bpf_ringbuf_submit(e, 0);
    return 0;
}

// 2. usb_control_msg (枚举控制传输)
SEC("kprobe/usb_control_msg")
int BPF_KPROBE(probe_usb_control_msg, struct usb_device *dev, unsigned int pipe, ...) {
    // 过滤 Standard Request (bmRequestType & 0x60 == 0)
    // 记录 bRequest (GET_DESCRIPTOR=6, SET_ADDRESS=5, SET_CONFIGURATION=9)
    // 记录 retval (负值即错误码)
    return 0;
}

// 3. hub_port_reset / usb_reset_device
SEC("kprobe/hub_port_reset")
int BPF_KPROBE(probe_hub_port_reset, struct usb_hub *hub, int port1, ...) {
    // 记录复位触发源、端口号、复位类型 (暖/冷)
    return 0;
}

char LICENSE[] SEC("license") = "GPL";

# analyze_enum.py
from bcc import BPF
b = BPF(src_file="usb_enum_tracer.bpf.c")
b["events"].open_ring_buffer(print_event)

def print_event(cpu, data, size):
    event = b["events"].event(data)
    # 关联 usbmon 抓包时间戳，构建完整时序图
    print(f"[{event.timestamp_ns/1e9:.6f}] {event.comm.decode()} PID:{event.pid} "
          f"Type:{event.event_type} Ret:{event.retval} VID:PID={event.vid:04x}:{event.pid:04x}")