Linux 如何找到未应用udev规则的原因？

我添加了一个udev规则来生成一个到特殊tty设备的单独链接。我从lsusb获取了供应商和产品id：

Bus 001 Device 016: ID abcd:1234 Foo Device

设备的

dmesg

输出为：

[  369.384850] usb 1-1.1: new full-speed USB device number 4 using xhci_hcd
[  369.470492] usb 1-1.1: New USB device found, idVendor=09d8, idProduct=0420
[  369.470506] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  369.470515] usb 1-1.1: Product: TWN4/B1.06/CCL3.12/PRS1.04
[  369.470522] usb 1-1.1: Manufacturer: OEM
[  369.475188] cdc_acm 1-1.1:1.0: ttyACM0: USB ACM device

通常，Debian系统会为此设备生成ACM*tty：

$ ls /dev/ttyACM*
/dev/ttyACM0

所以我创建了

/ect/udev/rules.d/99 bizrid.rules

：

ACTION=="add", ATTRS{idVendor}=="09d8", ATTRS{idProduct}=="0420", SYMLINK+="ttyMyDevice"

但是

ls/dev/tty*

不显示

ttyMyDevice

我迄今为止所做的尝试没有成功：

正在运行udevadm触发器。这应适用新的udev规则

我重新启动了

我查看了udevadm test/dev/ttyACM0。我的udevrule显示在末尾。因此，我确信它没有被推翻。但我想知道“无法打开”的提示。然而，对于其他TTY，例如tty0或ttyS0，也存在此提示

我重新连接了USB设备

我尝试了另一个udev规则。此规则是100%正确的，因为我已将此规则用于其他设备。但它不适用于ttyACM0：

我想知道为什么这不起作用。

---

如何找到未应用udev规则的原因？

根据注释I，可以尝试以下方法来调试问题：

检查驱动程序

使用

dmesg

检查您正在使用的驱动程序，并确保它是通用驱动程序。如果是自定义编译的，问题可能在自定义实现内部。如果它是通用的，请继续执行第二步。我在最后一行找到了驱动程序名：

cdc\u acm

[  369.384850] usb 1-1.1: new full-speed USB device number 4 using xhci_hcd
[  369.470492] usb 1-1.1: New USB device found, idVendor=09d8, idProduct=0420
[  369.470506] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  369.470515] usb 1-1.1: Product: TWN4/B1.06/CCL3.12/PRS1.04
[  369.470522] usb 1-1.1: Manufacturer: OEM
[  369.475188] cdc_acm 1-1.1:1.0: ttyACM0: USB ACM device

检查用户权限

确保您的udev规则的权限正确：

chmod 644 99-myrule.rules
chown root:root 99-myrule.rules

为添加操作执行测试运行

检查udevadm test-a add$（udevadm info-q path-n/dev/ttyACM0）的输出。我的输出如下所示：

呼叫：测试

version 232
This program is for debugging only, it does not run any program
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.

=== trie on-disk ===
tool version:          232
file size:         8447696 bytes
header size             80 bytes
strings            1849040 bytes
nodes              6598576 bytes
Load module index
Found container virtualization none
timestamp of '/etc/systemd/network' changed
timestamp of '/usr/lib/systemd/network' changed
timestamp of '/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Created link configuration context.
timestamp of '/etc/udev/rules.d' changed
Skipping overridden file: /lib/udev/rules.d/99-bizrfid.rules.
Reading rules file: /lib/udev/rules.d/50-firmware.rules

...

Reading rules file: /lib/udev/rules.d/98-systemd.rules
Reading rules file: /etc/udev/rules.d/99-bizrfid.rules
rules contain 49152 bytes tokens (4096 * 12 bytes), 12900 bytes strings
4244 strings (40114 bytes), 3517 de-duplicated (27942 bytes), 728 trie nodes used
GROUP 20 /lib/udev/rules.d/50-udev-default.rules:26
IMPORT builtin 'hwdb' /lib/udev/rules.d/60-serial.rules:7
IMPORT builtin 'usb_id' /lib/udev/rules.d/60-serial.rules:8
/sys/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0: if_class 2 protocol 0
IMPORT builtin 'hwdb' /lib/udev/rules.d/60-serial.rules:8
IMPORT builtin 'path_id' /lib/udev/rules.d/60-serial.rules:15
LINK 'serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0' /lib/udev/rules.d/60-serial.rules:16
IMPORT builtin skip 'usb_id' /lib/udev/rules.d/60-serial.rules:19
LINK 'serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00' /lib/udev/rules.d/60-serial.rules:23
LINK 'ttyMyDevice' /etc/udev/rules.d/99-bizrfid.rules:1
handling device node '/dev/ttyACM0', devnum=c166:0, mode=0660, uid=0, gid=20
preserve permissions /dev/ttyACM0, 020660, uid=0, gid=20
preserve already existing symlink '/dev/char/166:0' to '../ttyACM0'
found 'c166:0' claiming '/run/udev/links/\x2fserial\x2fby-id\x2fusb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00'
creating link '/dev/serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00' to '/dev/ttyACM0'
preserve already existing symlink '/dev/serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00' to '../../ttyACM0'
found 'c166:0' claiming '/run/udev/links/\x2fserial\x2fby-path\x2fpci-0000:00:14.0-usb-0:1.1:1.0'
creating link '/dev/serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0' to '/dev/ttyACM0'
preserve already existing symlink '/dev/serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0' to '../../ttyACM0'
creating link '/dev/ttyMyDevice' to '/dev/ttyACM0'
creating symlink '/dev/ttyMyDevice' to 'ttyACM0'
created db file '/run/udev/data/c166:0' for '/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0/tty/ttyACM0'
ACTION=add
DEVLINKS=/dev/serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0 /dev/serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00 /dev/ttyMyDevice
DEVNAME=/dev/ttyACM0
DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0/tty/ttyACM0
ID_BUS=usb
ID_MODEL=TWN4_B1.06_CCF3.00_PRS1.04
ID_MODEL_ENC=TWN4\x2fB1.06\x2fCCF3.00\x2fPRS1.04
ID_MODEL_FROM_DATABASE=Atom Processor Z36xxx/Z37xxx, Celeron N2000 Series USB xHCI
ID_MODEL_ID=0420
ID_PATH=pci-0000:00:14.0-usb-0:1.1:1.0
ID_PATH_TAG=pci-0000_00_14_0-usb-0_1_1_1_0
ID_PCI_CLASS_FROM_DATABASE=Serial bus controller
ID_PCI_INTERFACE_FROM_DATABASE=XHCI
ID_PCI_SUBCLASS_FROM_DATABASE=USB controller
ID_REVISION=0200
ID_SERIAL=OEM_TWN4_B1.06_CCF3.00_PRS1.04
ID_TYPE=generic
ID_USB_CLASS_FROM_DATABASE=Communications
ID_USB_DRIVER=cdc_acm
ID_USB_INTERFACES=:020201:0a0000:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=OEM
ID_VENDOR_ENC=OEM
ID_VENDOR_FROM_DATABASE=Intel Corporation
ID_VENDOR_ID=09d8
MAJOR=166
MINOR=0
SUBSYSTEM=tty
TAGS=:systemd:
USEC_INITIALIZED=71480300178
Unload module index
Unloaded link configuration context.

---

对于

udev

规则

/ect/udev/rules.d/99 bizrid.rules

我将添加

子系统

：

ACTION=="add", SUBSYSTEM=="tty", ATTRS{idVendor}=="09d8", ATTRS{idProduct}=="0420", SYMLINK+="ttyMyDevice"

您还可以添加

ATTRS{manufacturer}=

，但是

idVendor

和

idProduct

就足够了

否则，它看起来是正确的，测试运行将创建符号链接：

---

创建链接“/dev/ttyMyDevice”到“/dev/ttyACM0”

您能否与我们共享

dmesg

输出的有效部分？它还将帮助我们了解它是什么类型的USB设备以及实际值。谢谢。现在你用什么驱动程序？你有通用的还是自定义编译的？我询问的原因是，如果您检查-我看不到您的

idVendor=09d8，idProduct=0420

supported.Ok。如果您执行

udevadm测试-a add$（udevadm info-q path-n/dev/ttyACM0）

返回什么？您应该将信息添加到问题中，而不是作为问题的答案。啊，你是以root用户身份运行的，那么应该可以了。原因是

无效的规则/etc/udev/rules.d/99。规则：1:无效的操作操作

。请给我们看一下实际的

99 bizrfid。规则

规则不像您在问题中所做的那样是存根。@tukan非常感谢您的帮助。A现在添加了

99.bizrfid.rules

的

cat

。这几乎是一样的。发生“无效规则…”错误是因为我今天早上尝试了其他操作，但忘记了

=

。规则现在与引用的规则完全相同，我更新了udevadm测试的输出…。很抱歉搞混了，太好了！这管用！但是运行udevadm触发器是不够的。我需要运行

udevadm触发器

和

udevadm测试-添加…

。或者完全重新启动。您是如何找到udev规则不适用的原因的？@eDeviser Great；）。是的，

udevadm触发器

是不够的。您需要添加规则，否则大多数人会在之后重新启动。我是怎么发现的？我想说的是经验和排除所有其他可能性。对于此类基于linux/unix的问题，您会发现更适合。请不要忘记接受它-。如果

udevadm触发器

不起作用，它就不是解决方案。还有别的地方不对劲…@0andriy他把规则写错了。重新启动后它是否工作？为什么会出错？因为你需要重新启动。这是违反Unix方式的。

version 232
This program is for debugging only, it does not run any program
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.

=== trie on-disk ===
tool version:          232
file size:         8447696 bytes
header size             80 bytes
strings            1849040 bytes
nodes              6598576 bytes
Load module index
Found container virtualization none
timestamp of '/etc/systemd/network' changed
timestamp of '/usr/lib/systemd/network' changed
timestamp of '/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Created link configuration context.
timestamp of '/etc/udev/rules.d' changed
Skipping overridden file: /lib/udev/rules.d/99-bizrfid.rules.
Reading rules file: /lib/udev/rules.d/50-firmware.rules

...

Reading rules file: /lib/udev/rules.d/98-systemd.rules
Reading rules file: /etc/udev/rules.d/99-bizrfid.rules
rules contain 49152 bytes tokens (4096 * 12 bytes), 12900 bytes strings
4244 strings (40114 bytes), 3517 de-duplicated (27942 bytes), 728 trie nodes used
GROUP 20 /lib/udev/rules.d/50-udev-default.rules:26
IMPORT builtin 'hwdb' /lib/udev/rules.d/60-serial.rules:7
IMPORT builtin 'usb_id' /lib/udev/rules.d/60-serial.rules:8
/sys/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0: if_class 2 protocol 0
IMPORT builtin 'hwdb' /lib/udev/rules.d/60-serial.rules:8
IMPORT builtin 'path_id' /lib/udev/rules.d/60-serial.rules:15
LINK 'serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0' /lib/udev/rules.d/60-serial.rules:16
IMPORT builtin skip 'usb_id' /lib/udev/rules.d/60-serial.rules:19
LINK 'serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00' /lib/udev/rules.d/60-serial.rules:23
LINK 'ttyMyDevice' /etc/udev/rules.d/99-bizrfid.rules:1
handling device node '/dev/ttyACM0', devnum=c166:0, mode=0660, uid=0, gid=20
preserve permissions /dev/ttyACM0, 020660, uid=0, gid=20
preserve already existing symlink '/dev/char/166:0' to '../ttyACM0'
found 'c166:0' claiming '/run/udev/links/\x2fserial\x2fby-id\x2fusb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00'
creating link '/dev/serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00' to '/dev/ttyACM0'
preserve already existing symlink '/dev/serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00' to '../../ttyACM0'
found 'c166:0' claiming '/run/udev/links/\x2fserial\x2fby-path\x2fpci-0000:00:14.0-usb-0:1.1:1.0'
creating link '/dev/serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0' to '/dev/ttyACM0'
preserve already existing symlink '/dev/serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0' to '../../ttyACM0'
creating link '/dev/ttyMyDevice' to '/dev/ttyACM0'
creating symlink '/dev/ttyMyDevice' to 'ttyACM0'
created db file '/run/udev/data/c166:0' for '/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0/tty/ttyACM0'
ACTION=add
DEVLINKS=/dev/serial/by-path/pci-0000:00:14.0-usb-0:1.1:1.0 /dev/serial/by-id/usb-OEM_TWN4_B1.06_CCF3.00_PRS1.04-if00 /dev/ttyMyDevice
DEVNAME=/dev/ttyACM0
DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0/tty/ttyACM0
ID_BUS=usb
ID_MODEL=TWN4_B1.06_CCF3.00_PRS1.04
ID_MODEL_ENC=TWN4\x2fB1.06\x2fCCF3.00\x2fPRS1.04
ID_MODEL_FROM_DATABASE=Atom Processor Z36xxx/Z37xxx, Celeron N2000 Series USB xHCI
ID_MODEL_ID=0420
ID_PATH=pci-0000:00:14.0-usb-0:1.1:1.0
ID_PATH_TAG=pci-0000_00_14_0-usb-0_1_1_1_0
ID_PCI_CLASS_FROM_DATABASE=Serial bus controller
ID_PCI_INTERFACE_FROM_DATABASE=XHCI
ID_PCI_SUBCLASS_FROM_DATABASE=USB controller
ID_REVISION=0200
ID_SERIAL=OEM_TWN4_B1.06_CCF3.00_PRS1.04
ID_TYPE=generic
ID_USB_CLASS_FROM_DATABASE=Communications
ID_USB_DRIVER=cdc_acm
ID_USB_INTERFACES=:020201:0a0000:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=OEM
ID_VENDOR_ENC=OEM
ID_VENDOR_FROM_DATABASE=Intel Corporation
ID_VENDOR_ID=09d8
MAJOR=166
MINOR=0
SUBSYSTEM=tty
TAGS=:systemd:
USEC_INITIALIZED=71480300178
Unload module index
Unloaded link configuration context.

ACTION=="add", SUBSYSTEM=="tty", ATTRS{idVendor}=="09d8", ATTRS{idProduct}=="0420", SYMLINK+="ttyMyDevice"