discrete device

Character Device Driver: 1. Generally, we use APIs that dynamically allocate device numbers: Int alloc_chrdev_region (dev_t * Dev, unsigned int firstminor, unsigned int count, char * Name ); Dev is a function used for output. After successful call, the first number of the allocated range will be saved. Void unregister_chrdev_region (dev_t first, unsigned int count ); The above function allocates

During the project development, we need a USB-to-relay device to control the wireless transmitter device when the switch is enabled. When purchasing the device, the sourcing department buys a batch of devices without knowing the operating environment of the relay device, later, we found that the

1, the system under the same time hold down the keyboard "Windows" and "X" key to open the System menu, select "Device Manager." See figure below 2, Device Manager to select the device to uninstall the double-click, pop-up Drop-down menu will appear to uninstall the driver. Right-click "Uninstall" on the selected

1, the system under the same time hold down the keyboard "Windows" and "X" key to open the System menu, select "Device Manager." See figure below 2, Device Manager to select the device to uninstall the double-click, pop-up Drop-down menu will appear to uninstall the driver. Right-click "Uninstall" on the selected

Reason:Is that the virtual machine service is not turned onWorkaround: (Run as Administrator)Click "Start → run", enter CMD in the Run box to open a command prompt, then execute the following command in turn.net start VMCInet start vmx86net start Vmnetuserifsc config Vmci=autosc config Vmx86=autosc config Vmnetuserif=autoVMware cannot open the kernel device "\\.\global\vmx86": the system cannot find the file specified. Have you rebooted after installi

Now, let's write our own first character device driver--light LEDs. (Imperfect, back to perfect) Hardware platform: Exynos4412 (FS4412) Writing the drive is divided into the following steps: A--View the schematic, data manual, understand the equipment operation method; B-Find a similar driver in the kernel, develop it as a template, and sometimes need to start from scratch; C-Implement driver initialization: For example, register the driver with the

Failure phenomenon: When the WIN10 system uses a PIN to log on, it sometimes prompts "your device is offline, please log in with the last password used on this device." Solution: This time need to connect the network, re-enter the password to log in, you can connect to the wired network or wireless network, the following describes the connection network solution. 1. Click on the wireless i

When debugging, it is found that there is no selected device or the selected device Xcode does not support: Workaround: 1. Download the DMG you need on the Internet to find out if you have any https://pan.baidu.com/s/1pLoxkDH?errno=0errmsg=Auth%20Login%20Sucess. bduss=ssnerror=0traceid= #list/path=%2f 2.Finder Click "Apps" to find Xcode, right click to select "Show Package Contents" and go to "Con

Turn off eclipse. Turn Adb.exe off in Task Manager Enter the ADB directory and then execute the ADB start-server to successfully execute the problem resolution 　　The problem should be solved, but if adb start-server start up!Finally, the reason for the port occupancy is found.Here's how to fix it:1.adb nodaemon serverTo view the reasons that cannot be performed, output: Cannot bind ' tcp:5037 ' 2. Fixed a problem with the port! Yes, Port 5037 is occupied!3.netstat -ano | findstr

Platform device registration analysis:/* for the following resources, read the chip manual and view the schematic diagram */---------------------------------------------------------ARCH/ARM/plat-s3c24xx/Devs. c/* Most device controller resources are defined here *//* LCD controller */Static struct resource maid [] = {[0] = {. Start = s3c24xx_pa_ LCD,. End = s3c24xx_pa_ LCD + s3c24xx_sz_ LCD-1,. Flags = iore

One: Load good sbull drive[Email protected]:/# ls/dev/sbull-l brw-r--r--1 root root 254, Mar 08:25/dev/sbull [email protected]:/#You can see that the Sbull file property is a block device, the main device number is 254, the secondary device number is 16Second: Partition the device[Email protected]:/# fdisk/dev/sbull [2

Linux device drivers are in the form of kernel modules, but the modules are not necessarily drivers. The driver can be compiled into the kernel, when configuring the kernel, if a configuration item is set to M, then it will be compiled with the kernel compiled into a module, but to add drivers to the kernel will make the kernel very large, and in addition, modify, delete the driver need to compile the kernel again, this is extremely troublesome. So th

Now the network is more and more common, more and more knowledge, the need for more memory, so the U disk is more and more widely used. All we have to do is to have a small U-plate to store all the files. But we also had a little trouble using the U disk. After we use the U disk, the Win7 system prompts "The device is in use" when it exits safely. Close any programs or windows that may be using the device,

Tags: adb shell multi-device adbIn our usual use of the ADB tool, you may encounter such problems, when the computer is linked to multiple devices, the simple use of the ADB shell link device, there will be an error. Let's take a specific look at how to deal with this situation: 1. First, we need to know which devices are linked to each other on the computer. Use the following command to return to the

Block device installation, create, map, mount, details, adjust, uninstall, curve map, deleteMake sure your ceph storage cluster is active + clean before working with ceph block devices.vim/etc/hosts172.16.66.144 ceph-clientPerform this quick boot on the admin node.1. On the admin node, install Ceph on your ceph-client node with Ceph-deployCeph-deploy Install Ceph-client2. On the admin node, copy the Ceph configuration file and ceph.client.admin.keyrin

Reprinted from: http://www.yeeyan.com/articles/view/jht/57657 Introduction Unknown device, no longer headache! Rule 1: do not lose the drive disc of the device. Rule 2: exercise caution when saving a backup. Rule 3: If your driver file is lost, you need to know where to download it. Congratulations! If you do not care about the above two items, this article can free you from the three serious crimes you ha

The Win8 method for disabling a device in Device Manager is as follows: 1. At the same time, hold down the "Windows logo" and "X" keys on the keyboard, and open the Device Manager at the System tool shortcut entrance. 2. Before the device class you want to disable, click to expand the view of the

Device content As we all know, the device context is a Windows data structure that contains information about the drawing properties of a device, such as a display or printer. All painting calls are performed through the device context object, including the paint brush, bitmap, and painting brush. The

(void *start, size_t length);3. Virtual Memory Area:The virtual memory area is a homogeneous interval in the virtual address space of the process, that is, a contiguous address range with the same characteristics. The memory image of a process consists of the following parts: program code, data, BSS and stack areas, and memory-mapped regions.The Linux kernel uses the VM_AREA_STRUCT structure to describe the virtual memory area. Its main members:unsigned long vm_start; /* Our start address withi

Win10 after the update, Bluetooth function is gone, there is no option to open the Device Manager, there is an unknown USB device, reboot invalid, reload Bluetooth driver is invalid, Bluetooth in the BIOS is open.Try to find all the methods on the Internet, including Update WIN10 update, update Bluetooth driver, etc. are not resolved,Solutions are:1. Open the Device