udev

Embedded linux filename length

由 烂漫一生 提交于 2019-12-11 05:09:38
问题 I am using an arm development platform. There I installed udev and it works perfect. But when I mount a pen drive and see the file content all files and folders with names having more than 8 chars have been replaced with "~" char. eg: myfilename.mp3 is replaced with myfile~e.mp3 Before udev installation it worked well. (All file names appeared normally). What should I do? thank you. 回答1: This is not related to filename length limitation in Linux. This happened because this drive was mounted

Use iSerialNumber USB device descriptor to uniquely identify GoPro Camera

由 强颜欢笑 提交于 2019-12-11 03:58:47
问题 The field I'm interested is iSerial from the output of: lsusb -d <idVendor>:<idProduct> -v Example output of a non-unique iSerialNumber: Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 239 Miscellaneous Device bDeviceSubClass 2 ? bDeviceProtocol 1 Interface Association bMaxPacketSize0 64 idVendor 0x0402 ALi Corp. idProduct 0x9665 Gateway Webcam bcdDevice 0.09 iManufacturer 3 iProduct 1 iSerial 0 <-- Three string descriptors exist to provide details of the manufacturer

How to enumerate USB devices *and* read/write to them?

由 强颜欢笑 提交于 2019-12-11 00:43:04
问题 There is a custom USB device I need to communicate with. There is no particular driver for it. The device doesn't show as /dev/tty* . I found out how I can use libudev to enumerate the USB devices and let's say I manage to get the corresponding struct udev_device . What I can't figure out is how I can open(2) the device so I can write(2) to and read(2) from it. Is it possible to communicate with a generic USB device, setting baudrate and just read/write? If so, what "file" should I open after

Create openCV VideoCapture from interface name instead of camera numbers

由 ＊爱你＆永不变心＊ 提交于 2019-12-10 04:25:00
问题 The normal way to create a videocapture is this: cam = cv2.VideoCapture(n) where n corresponds to the number of /dev/video0 , dev/video1 But because I'm building a robot that uses multiple cameras for different things, I needed to make sure that it was being assigned to the correct camera, I created udev rules that created devices with symbolic links to the correct port whenever a specific camera was plugged in. They appear to be working because when I look in the /dev directory I can see the

linux命令

由 巧了我就是萌 提交于 2019-12-09 20:43:55
修改网卡参数：vi /etc/sysconfig/network-scripts/ifcfg-eth0 重启网卡：start_udev service network restart 设置计算机名称：vi /etc/sysconfig/network 来源： https://www.cnblogs.com/zyj747865041/p/12013251.html

Linux 中修改网卡名称【ubuntu + Centos7】

由 感情迁移 提交于 2019-12-09 20:38:44
　　有时候安装好Linux系统之后，网卡的名称不是ethX， 这时候可以通过以下方式修改网卡的名称为ethX（以eth0为例）。 ubuntu 14.04 　　1. 查看是否存在/etc/udev/rules.d/70-persistent-net.rules 文件，如不存在，可以通过以下方式生成（或者从其它机器上拷贝一个） # ifconfig em1 Link encap:以太网 硬件地址 18:66:da:7e:64:10 inet 地址:192.168.2.38 广播:192.168.2.255 掩码:255.255.255.0 inet6 地址: fe80::1a66:daff:fe7e:6410/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 跃点数:1 接收数据包:328617 错误:0 丢弃:7944 过载:0 帧数:0 发送数据包:80911 错误:0 丢弃:0 过载:0 载波:0 碰撞:0 发送队列长度:1000 接收字节:35848013 (35.8 MB) 发送字节:11969732 (11.9 MB) 中断:74 Memory:95000000-957fffff # export INTERFACE="em1" # export MATCHADDR="18:66:da:7e:64:10" #

udevadm vs linux hotplug

由 别说谁变了你拦得住时间么 提交于 2019-12-08 07:30:58
问题 I am a bit confused with the questions listed below: While I execute udevadm on my desktop, it is able to listen uevent sent from kernel. I think before the execution of udevadm , it will check the availability of udevd . That means, if the udevd is not available on my desktop, udevadm will not be able to work. Is my thinking correct? To have the same functionality of udevadm , I found that linux also provides another way to archive this. It's called netlink . What confuses me is If I do

Run script with udev after USB plugged in on RPi

由 为君一笑 提交于 2019-12-08 06:01:45
问题 I am trying to run a script from a udev rule after any USB drive has been plugged in. When I run the script manually, after the USB is mounted normally, it will run fine. The script calls a python program to run and the python program uses a file on the USB drive. No issues there. If I make the script to simply log the date in a file, that works just fine. So I know my UDEV rule and my script work fine, each on their own. The issue seems to come up when udev calls the script, then script

how uevents get triggered in kernel

由 狂风中的少年 提交于 2019-12-07 23:05:00
问题 uevents has been sent from kernel space to user space through netlink socket. In kernel, there must be something trigger uevent. I guess there are two possibilities: Hardware interrupt - this means, once hardware interruption happened, kernel sends event to user space to signal that there is some events happened. software polling - this means, there is always a daemon to check these file system to see if there is anything changed. If so, then update these info to upper layer. Could anyone

Getting Notified on “Ethernet cable plugged in” events in linux

由 旧城冷巷雨未停 提交于 2019-12-07 19:39:42
问题 I am writing a Python Application running on linux. I want to be able to register and be notified by the system if a network cable is plugged in/ out . I am already using pyUdev (python bindings for libUdev) in order to get notified for USB plug in events. However, because the network eth0 module (for example) always remains loaded (regardless of the cable being plugged in) , I dont get the information I require. It only works for if up/down events. I have read a lot of posts on Windows WMI
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