Tài liệu Linux Device Drivers-Chapter 16 :Physical Layout of the Kernel Source ppt

... description of this mechanism at http://www .linux. it/kerneldocs/sysctl. ipc and lib Chapter 16 :Physical Layout of the Kernel Source So far, we've talked about the Linux kernel from the perspective ... through the source code and grepping your way through the source tree to uncover the relationships among the different parts of the kernel. This kind of "heavy grepping" is one of the ... in their own source trees. The kernel directory of the source tree includes all other basic facilities. The most important such facility is scheduling. Thus, sched.c, together with < ;linux/ sched.h>,...

Tài liệu Linux Device Drivers-Chapter 6 : Flow of Time pptx

... Fortunately, the kernel makes a number of facilities available to ease the task of the driver writer. In the next few chapters we'll fill in information on some of the kernel resources that ... actually run (it calls the scheduler, which selects the same process, which calls the scheduler, which ). In other words, the load of the machine (the average number of running processes) will ... architectures. The former uses a software loop to delay execution for the required number of microseconds, and the latter is a loop around udelay, provided for the convenience of the programmer. The...

Tài liệu Linux Device Drivers-Chapter 15 :Overview of Peripheral Buses pdf

... in the required registers, whereas the contents of the optional registers depend on the actual capabilities of the peripheral. The optional fields are not used unless the contents of the required ... to the last device that has been found, so that the search can continue instead of restarting from the head of the list. To find the first device, from is specified as NULL. If no (further) device ... proceed in one of two ways. The easier path is using the resources that Linux already offers via /proc/bus/pci, although these were not available in version 2.0 of the kernel. The alternative...

Tài liệu USB in a Nutshell - Making Sense of the USB Standard ppt

... the interface between the hardware of the function device and the firmware running on the function device. All devices must support endpoint zero. This is the endpoint which receives all of the ... follows. The host will send the Setup token telling the function that the following packet is a Setup packet. The Address field will hold the address of the device the host is requesting the descriptor ... load of 16. 5K ohms on a VTERM of typically 3.3v.Therefore this resistor sinks 200uA before we even start.Another consideration for many devices is the 3.3V regulator. Many of the USB devices...

Tài liệu Lab 3.2.5 Configuring Message-of-the-Day (MOTD) pptx

... Test the MOTD display a. Exit the console session. Reenter the router to display the message -of- the- day. This is done by pressing the Enter key. This will display the message entered into the ... Message -of- the- Day (MOTD) Objective • Demonstrate the commands to enter a message -of- the- day (MOTD) on the router. This procedure allows all users to view the message upon entering the router. ... information a. On the Gadsden router, enter the global configuration mode. Configure the hostname as shown in the chart. Then configure the console, virtual terminal and enable passwords. If there are...

Tài liệu Linux Device Drivers-Chapter 1 :An Introduction to Device Drivers ppt

... Introduction to Device Drivers As the popularity of the Linux system continues to grow, the interest in writing Linux device drivers steadily increases. Most of Linux is independent of the hardware ... makes Linux drivers easy to write, to the point that there are now hundreds of them available. There are a number of reasons to be interested in the writing of Linux device drivers. The rate ... transmission. Other classes of driver modules exist in Linux. The modules in each class exploit public services the kernel offers to deal with specific types of devices. Therefore, one can talk of universal...

Tài liệu Linux Device Drivers-Chapter 2 : Building and Running Modules pptx

... when playing with the kernel sources, as most of the time you'll end up with several versions of the source tree. All of the sample modules accompanying this book use the KERNELDIR variable ... description of the internals applies only to versions 2.2 and 2.4 of the kernel; Linux 2.0 did the same job in a different way. The compiler will define the symbol for you whenever you include < ;linux/ module.h> ... over from the kernel the task of being the single agent in charge of hardware control. Client applications can then connect to the server to perform actual communication with the device; a...

Tài liệu Linux Device Drivers-Chapter 3: Char Drivers docx

... four is the default in the scull sources. The last few lines of the script may seem obscure: why change the group and mode of a device? The reason is that the script must be run by the superuser, ... char *name); The arguments are the major number being released and the name of the associated device. The kernel compares the name to the registered name for that number, if any: if they differ, ... across the computer architectures on which Linux runs. On the other hand, the device doesn't do anything "useful" other than demonstrating the interface between the kernel and...

Tài liệu Linux Device Drivers-Chapter 4 : Debugging Techniques pptx

... displays the processor status at the time of the fault, including the contents of the CPU registers, the location of page descriptor tables, and other seemingly incomprehensible information. The ... return the number of bytes of data actually placed in the page buffer, just like the read implementation does for other files. Other output values are *eof and *start. eof is a simple flag, but the ... a PC running version 2.4 of the kernel. The most relevant information here is the instruction pointer (EIP), the address of the faulty instruction. Unable to handle kernel NULL pointer dereference...

Tài liệu Linux Device Drivers-Chapter 5 : Enhanced Char Driver Operations pptx

... represents. When copies of the device are created by the software driver, we call them virtual devices just as virtual consoles use a single physical tty device. Although this kind of access control ... jump directly to the next section. The /dev/scullpriv device node implements virtual devices within the scull package. The scullpriv implementation uses the minor number of the process's ... codes, these codes have been split up into several bitfields. The first versions of Linux used 16- bit numbers: the top eight were the "magic'' number associated with the device, ...

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