./////////////////////////////////////////////////////////////////////////////////////////////////////////////// ////When your device is idle, it will first darken the screen, then turn off the mask (that is, the black screen, you have to press the power key and so on to re-charge it), will eventually turn off the phone's CPU, the purpose is to prevent the device's battery quickly exhausted, but many times, your program may request some unusual behavi
In the article on the Linux System file type classification we mentioned the block device and the character device file, then what is the block device character device file? What are the fundamental differences between them?The device files are divided into blocks (block)
See Dr. Zhao Jiong's "Linux 0.11 source code comment" has been two or three weeks, starting from today, some personal summary and sentiment sub-standard inscribed out, chat for memory for later review.In the/linux/boot/bootsect.s of linux0.11 source code, there is a label definition Root_dev! Root_dev:0x000-same type of floppy as boot.! 0x301-first partition on First drive etcRoot_dev = 0x306Here, Root_dev is the device number of the system-specified
Device numberThe device number consists of the main device number and the secondary device number. Linux, all devices are files, all devices can find the corresponding files in the/ dev directory. These files, in addition to their names, have different device numbers for eac
From: http://www.cnblogs.com/zhuyp1015/archive/2012/05/22/2514008.html bird1015 blog
When writing a Linux kernel driver, if you do not dynamically generate a device number, you need to manually allocate the device number. It is possible that the device number you allocate will be the same as the existing device number
Device number:1, self-allocation of the initiativeMajor = Register_chrdev (0, "First_drv", first_sdv_fops);//RegisterWhen you register your device with the device number 0, the kernel will voluntarily assign a master device number to return.2. Manual designationFind the main device
The character device or block device definition belongs to the device access layer of the operating system, which is not necessarily related to the characteristics of the actual physical device.
The driver is under the device access layer, so you only need to provide the dri
This article was reproduced from: http://blog.csdn.net/ymangu666/article/details/39292651Primary, secondary device numberThe application can access the actual device by reading and writing to the device files in the/dev directory.1) Each device file corresponds to two device
According to ldd3, the Linux device model can be considered as an advanced textbook, which is unnecessary for most program authors. But I personally think: For an embedded Linux underlying programmer, this part of content is very important. For example, I learned about ARM9. many bus (such as SPI, IIC, IIS, and so on) have been written into subsystems in Linux, and no driver needs to be written by myself; unlike PCI, USB, and other tutorials on ldd3,
Linux character device-simple character device model
Linux character Devices
I. Use the character Device Driver
1. Compile/install the driverIn Linux, drivers generally use the program structure of the kernel module for encoding. Therefore, the essence of compiling/installing a driver is to compile/install a kernel module.
2. Character
Android Device Manager Vulnerability 2: prevents users from activating the Device Manager, android2 --
In June 2013, Russian security vendor Kaspersky found the most powerful mobile trojan in history-Obad. a. This Trojan exploits an unknown Android Device Manager Vulnerability (ANDROID-9067882). A mobile phone trojan that has activated the permission of the
/** * Author:hasen * Reference: Linux device Driver Development Details * Introduction: Android Small rookie Linux * device Driver Development Learning Journey * Topic: device drivers that support polling operations * DATE:2014-11-07 */
In
Globalfifo's poll () function, the r_wait and w_wait wait queue headers in the
Device files: block Device file B: A device that is randomly accessed by block;character device file C : by character, linear device;Common block device file B: HDDDevice file name for the hard disk device:IDE, ATA:HDSATA, SCSI, U
Linux MTD (Memory technology Device) subsystem analysisFor Atheros Char deviceRead the Linux MTD Source code Analysis to this part of the overall understanding, combined with the existing code, analysis of how Atheros MTD is used.Linux kernel:2.6.31.Atheros platform:qca9890???Refer to the Linux MTD Source code Analysis , where MTD is divided into 4 layers, from top to bottom: Character device node, characte
(i): Interrupt of block device:Interrupt function: the REQUEST_IRQ () function links the interrupt service subroutine of the block device driver to the specific interrupt request line.The interrupt procedure for the driver's interrupt service subroutine is as follows:(1): The user process emits a different type of input or output request (read () system call), perhaps firstThrough high-speed buffer storage, the actual
Some of the devices used in the computer are not used at all, or encountered some devices are not normal use, we can view these devices, through the Device Manager can be processor, hard drive, storage controller, monitor, keyboard, mouse devices, image equipment and network adapters and so on equipment operation and management, So how do you disable the specified device? Let's take a look at the specific s
In Unix-like operating systems,Loop Device,LoopbackDevice,VND(Vnode disk), orLofi(Loopback FileInterface) is a pseudo-device that makes a fileAccessible as a pseudo-device. A loop device may allow some kindData elaboration during this redirection; for example, the device may
A new set of driver management and registration mechanisms have been introduced from Linux 2.6:P latform_device and Platform_driver.Most of the device drivers in Linux can use this mechanism, the device is represented by Platform_device, and the driver is registered with Platform_driver.Compared with the traditional device driver mechanism (registration via Drive
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