13.3.1 fb0 ¶

The fb0 device exposes the framebuffer passed as part of the boot protocol, when present. The device uses Linux’s fbdev interface.

13.3.2 ps2keyboard/ps2mouse ¶

The devices ps2keyboard and ps2mouse exposes x86’s native PS2 interfaces, ps2keyboard is a normal character device that returns scancodes as they are received. ps2mouse is a character device that returns mouse packets following the structure:

struct mouse_data {
   int x_variation;
   int y_variation;
   int z_variation;
   bool is_left_click;
   bool is_right_click;
   bool is_middle_clock;
   bool is_4th_click;
   bool is_5th_click;
};

ps2mouse supports a series of ioctl calls for setting different modes and talking directly with the PS2 controller:

PS2MOUSE_2_1_SCALING     = 1
PS2MOUSE_1_1_SCALING     = 2
PS2MOUSE_SET_RES         = 3
PS2MOUSE_SET_SAMPLE_RATE = 4

ioctl(mouse, PS2MOUSE_2_1_SCALING, ignored);  // Enable 2:1 scaling.
ioctl(mouse, PS2MOUSE_1_1_SCALING, ignored);  // Enable 1:1 scaling.
ioctl(mouse, PS2MOUSE_SET_RES, resolution);   // (0 - 3).
ioctl(mouse, PS2MOUSE_SET_SAMPLE_RATE, rate); // (0 - 200).

Valid resolutions and sample rates are values for the PS2 controller, else the call is ignored. For valid values and their meaning refer to this website.

13.3.3 serial ¶

The devices starting by serial represent the several character devices used for each present serial port, they support read/write operations, but no TTY interface is exposed, they are raw byte streams.

Baud and other settings can be set by using the termios, note that most of the fields are not implemented as the serial devices are not ttys but just byte streams.

The default baud for all ports is set to be 115200.