About frame buffering under Linux

The FB device provides an abstract layer of graphics hardware that represents a frame buffer of some video hardware, and the frame buffer can be directly accessed (/ dev / fb *) through the specification-defined interface. Our familiar XWindows has a non-accelerated X server, XF86_fbdev is using frame buffer drivers, the driver appeared in the XFree86 3.2 version, is now very mature. Frame buffer is different in various graphics hardware, such as the ATI RAGE 128 provides its own frame buffer, Cirrus Logic, Matrox, PowerVR 2, has its own frame buffer, TGA, VESA, is two frame buffer equipment standards, VESA due to It is more widely used by most modern graphics cards. Different frame buffers need to use different drivers when kernel compile. So you want to use a frame buffer to have a display card with frame buffer. And different graphics cards have different support capabilities of frame buffering, such as the resolution mode (1024 * 768 or 800 * 600), and its color depth.

FB The purpose of Linux was originally in order to start the LINUX kernel start, showing Linux logo icon (small penguin), in order to increase the kernel (if it feels a bit boring), this thing is not entered by the kernel. Before the protection mode, the graphics card mode is placed in FB mode with the help of the BIOS. Of course, we will not switch back, because everyone knows that we cannot use the underlying BIOS function in the 80x86 protection mode. Of course, I will start using it to provide a larger font and display resolution for the Linux text console (such as 1024 * 768 32-bit color), and can use very cool fonts to distinguish the boring text of the 80x25 column. Font. For example, you can make Linux text in the hacker's computer in the Hero Empire. After Linux 2.0, you can add a VGA = Let Linux enter the frame buffer at startup The console mode, the Linux core mode number is as follows: Linux kernel mode number = VESA mode number 0x200 So the Linux core mode number is shown below | 640x480 800x600 1024x768 1280x1024 ---- ----------- ------------------------ 256 | 0x301 0x303 0x305 0x30732k | 0x310 0x313 0x316 0x31964k | 0x311 0x314 0x317 0x31a16m | 0x312 0x315 0x318 0x31b if startup In most cases the problem of graphics card.

Later, someone used it to provide language platform for other national languages, such as our Chinese platform ENCON, using FB to display Chinese fonts. Of course, there is the X Server mentioned earlier: XF86_fbdev

Then say two sentences, for / dev / fb * can access the frame buffer storage as an access to normal files. I hope that everyone will use good frame buffers, and experience Linux to provide us with fun.