All Questions
Tagged with framebuffer linux-kernel
27
questions
1
vote
2
answers
504
views
Linux simple-framebuffer is not detected by kernel
I'm trying to get the simple-framebuffer working in Linux, so that I can use a region in System RAM as a framebuffer.
I'm running Linux kernel v5.10.7 on a RISC-V system.
So far, I have enabled ...
- 11
0
votes
1
answer
472
views
Cannot find and load fbtft module, even if it was enabled in .config
I've been trying to enable fbtft module on a minimal buildroot image for an Orangepi zero board. I've enabled it under Device Drivers > Graphics Support > Frame Buffer Devices > using make ...
- 506
1
vote
0
answers
434
views
Linux framebuffer not updating when using KD_GRAPHICS
I've been trying to do some old-school drawing on the Linux framebuffer. I'm aware this is not the "modern" way to do things but exploring it out of curiosity. I am confused that my screen ...
- 56
0
votes
0
answers
977
views
Why doesn't writing to /dev/fb0 work on some video cards
I have a simple embedded Linux build that boots from a USB and has a framebuffer. There are simple bash scripts that write to the /dev/fb0 device to give user feedback and clear the screen, along ...
- 248
1
vote
0
answers
203
views
Which frame ? - Linux framebuffer alternate
I read the Linux framebuffer dev/fb0 with mmap().
But it is an alternative framebuffer, so I get two images.
In one hand : char * map0 = (char *) mmap(nullptr, width*height*4, PROT_READ, MAP_SHARED, ...
- 11
2
votes
1
answer
1k
views
Linux device driver for display | Framebuffer
I am studying the display device driver for linux that runs TFT display, now framebuffer stores all the data that is to be displayed.
Question: does display driver have equvalant buffer of its own to ...
- 278
0
votes
1
answer
436
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Linux writing GPU drivers to print arbitrary outputs from kernel side
I have questions about GPU drivers for linux kernel.
1-) Is it possible to write a custom kernel module to print words or colors on screen like VGA using a GPU over PCI express ?
2-) If it is, is ...
- 456
0
votes
0
answers
113
views
Userspace code not calling framebuffer write cb
I have written a custom QEMU framebuffer device. In support of this I also wrote a framebuffer driver for Linux. cat /dev/urandom > /dev/fb0 works wonderfully and calls my fb_write callback (...
- 585
4
votes
0
answers
242
views
Linux framebuffer detect change
I would like to detect when framebuffer is chaning on linux framebuffer without X.
Where should I look into to find it? driver, kernel, a user space code? I know I can use cp /dev/fb0 fb0 to copy ...
- 41
1
vote
0
answers
251
views
How to open /dev/graphics/fb0 in kernel space?
I want to open /dev/graphics/fb0 from kernel space and write to it to display a test pattern. Is there any way I can do that?
There is one question related to this. But, in the answer, it's done ...
- 751
4
votes
0
answers
189
views
Drawing an image on the screen during initramfs
I'm trying to draw an error image during initramfs on a base ubuntu 18.04 image.
My issue is that when I write the image directly into /dev/fb0 The card only appears to redraw areas of the screen the ...
- 45.7k
10
votes
1
answer
4k
views
What is the relationship between framebuffer, VT, and tty?
I'm now studying what is the mechanism behind Ctrl+Alt+F1~F7.
I found some infomation talk about framebuffer, VT, and tty. I know framebuffer is an anstraction to graphic card manipulation and tty(and ...
- 101
6
votes
3
answers
7k
views
How to get RGB pixel values from Linux framebuffer?
I want to get RGB values of screen pixels in the most efficient way, using Linux. So I decided to use the framebuffer library in C (fb.h) to access the framebuffer device (/dev/fb0) and read from it ...
- 864
0
votes
0
answers
110
views
How does a kernel panel driver specify the xstep value
I'm working on an LCD panel driver for an embedded device with a Atmel sama5d2 based micro-controller under Linux.
The kernel version I'm working against is 4.4 as found here.
I'm using the drivers/...
- 658
0
votes
0
answers
498
views
Where is the endianness of the frame buffer device accounted for?
I'm working on a board with an at91 sama5d3 based device. In order to test the framebuffer, I redirected a raw data file to /dev/fb0. The file was generated using gimp and exported as a raw data file ...
- 658