Shulou(Shulou.com)06/01 Report--

Today, I will talk to you about how to parse the Linux APM registration structure with code. Many people may not know much about it. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

Because there is no bios device in the Linux APM system, we can only create a virtual character device for the Linux APM system to communicate with the user space. That is to say, the implementation of a misc device in Linux APM is essentially a character device. The main setting number of the misc device is 10, while the apm_bios as a misc device, the secondary setting number is 134.

The / drivers/char/apm-emulation.c of the Linux2.6.30.10 kernel provides the driver model of Linux APM_bios, which is the entry function for the system to go to sleep. The earlier version of the interface file is: arch/arm/kernel/apm.c

/ / the registration structure is:

Static struct file_operations apm_bios_fops = {.owner = THIS_MODULE, .read = apm_read, .poll = apm_poll, .ioctl = apm_ioctl, .open = apm_open, .release = apm_release,}; static struct miscdevice apm_device = {.minor = APM_MINOR_DEV, .name = "apm_bios", .fops = & apm_bios_fops}

In this way, we can read the relevant information about Linux APM_bios just like to a normal device file.

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