Questions tagged [framebuffer]

related to Linux `fbdev` abstraction (a.k.a. Linux framebuffer), as well as to accessing the framebuffer (a part of video memory) in general

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48 views

Write on /dev/fb0 has no effect on GUI console

I run X in this way /usr/bin/X vt07 -retro to have the GUI on console 7 and the gray grid as background. On console 1 I write while [ 1 ] ; do cat /dev/random > /dev/fb0; done and I see the ...
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Clear dequeued buffer of v4l2loopback device

Objective To clear the dequed buffer of v4l2loopback device Actual Error I am trying to execute a script as ffmpeg -stream_loop -1 -re -i sample-video.mp4 -vcodec rawvideo -threads 0 -f v4l2 /dev/...
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79 views

hwinfo --framebuffer shows nothing, can't change grub resolution

I am using a Lenovo Yoga C940 15" with Fedora 34. It has a 4K screen with an nvidia gtx1650 mobile card and integrated intel graphics. I wanted to change the resolution of the GRUB menu because ...
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10 views

Dual Display Application

I am developing a GUI application for Linux (Rasbian). I want this application to run on two screens ( /dev/fb0 and /dev/ fb1 ). The main application window with input fields to display on one screen (...
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linux kernel 5.10.x to 5.11.x : virtual terminal VT not available after booting and framebuffer switches from EFI VGA to Intel or AMD framebuffer

Previous kernel 5.10. Current kernel 5.11.4. After moving to 5.11, I can no longer switch to VT's. The boot sequence shows as far as fb0: switching to inteldrmfb from EFI VGA ... Console: switching to ...
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0answers
12 views

Crossplatform library that can handle keyboard events (including keyup/kedown) without X similar to the way SDL does it

I know there are ways to manually check keyboard events and check if it's keyup/down (regardless whether in framebuffer or window system) such as /dev/input/events* or ioctl, at least on Linux, like ...
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0answers
31 views

Is it possible to access the “frame buffer” so I can change the properties of each pixel?

I don't know if my question is technically correct. Here is what I want to do, I'm running linux with xorg. The colors on my screen is way too dull. Its not my hardware because when I had windows my ...
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2answers
409 views

How can I enable TTY console?

I'm running Linux (Debian 10) on a Chromebook (Eve) using a stock Chrome OS kernel (4.4.x) with minor modifications. Everything runs (mostly) fine except that TTY console cannot be accessed via Ctrl+...
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64 views

Correct way of editing frame buffer before Xorg show it on display

I am trying to find a way for applying some image processing effects over everything visible on my display. For example make everything black-white, or draw only edges of everything on screen. Natural ...
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22 views

Improve gradients when displaying application in the framebuffer

I'm developing an Qt GUI application which will be run on the Raspberry Pi 4 with Raspberry Pi Os 10 on it. I need it to run as fast as possible after the device is boot and the user should have ...
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1answer
348 views

Can't clear /dev/fb0

I have one of those 7" HDMI diplays from eBay, driving it with a Q1900 board running Ubuntu 20. I can write to the display using fbi: sudo fbi -a -T 1 --noverbose -d /dev/fb0 -t 5 --blend 1000 &...
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143 views

Out of disk space error when trying to write to frame buffer

I'm using this command: cat /dev/urandom >/dev/fb0 I tried it with both root and sudo and even then I'm shown that there is no disk space left. I'm using Fedora 29. I've checked the disk space, ...
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18 views

Simpleframebuffer driver not working

My current setup is Xclient -> X11-> framebuffer (/dev/fb0). I have configured the framebuffer as following framebuffer { compatible = "simple-framebuffer"; reg = <0x01D00000 (...
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2answers
3k views

cannot run in framebuffer mode. Please specify busIDs

from my previous question empty screen after booting from live persistent usb, I am able after boot to access all files and folders, but the X-server is unable to load (so I get only to tty1). From ...
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0answers
35 views

TTY size with dual monitors

I have two monitors connected with different resolutions (and aspect ratios): 1820x1080 (1.68) 3840x2160 (1.77) When switching to TTY it's shown on both screens at the same time, with the size (...
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0answers
14 views

Is it possible to run fb on one head and X on anohter, given one card connected to a TV and a monitor?

I would like to set up so that my computer's monitor is connected to it's VGA output, while having a framebuffer on the other head. Both heads seem to share a card. They work fine as part of the same ...
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0answers
252 views

Initializing framebuffer device without udev

I am trying to reduce boot time in a Raspberry Pi 4 using Yocto Linux. The system uses SysV init. There is psplash that uses framebuffer, and Qt application that uses DRM/eglfs, displayed ...
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0answers
53 views

X writing top of screen to random parts of framebuffer - Xorg problem?

I have an ASUS laptop with an SIS graphics card. The default Xorg generated when I installed Debian (well, technically Raspbian Desktop) was at 640x480, yet it can easily do better as it's a 1280x800 ...
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825 views

Cannot run in framebuffer mode. error help

I'm using ParrotSec and the system I normally used gave an error last night and I could not solve it. I start normally, then wait, but the KDE does not start and the screen remains black. I pressed ...
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204 views

How do I allocate memory for a framebuffer loadable kernel module (linux)

I'm writing a 'fake' framebuffer device so I can use my e-reader as an external screen for my raspberry pi. The e-reader part is working fine (https://github.com/llandsmeer/inkvt), but now I want to ...
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2answers
414 views

Cannot force Debian to start in Framebuffer 640x480 resolution

In order to port an embedded project from an ARM target to Linux/x86, I have to create a Debian VM (I'm using Virtualbox right now) which starts in framebuffer mode with 640x480 resolution. I used ...
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1answer
5k views

Debian10: No such file or directory: /dev/dri/card0

I'm installing Debian 10 but I cannot startx nor have a GUI. I think the problem is about some driver. Here are the errors I've got in /var/log/Xorg.0.log : [drm] Failed to open DRM device for pci:...
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3answers
1k views

How to access and use Linux Frame Buffer without GTK?

I'd like to use /dev/fb0 or whichever other files are provided by the linux. This in a system specific way as low as possible how to read/write/interpret those device files for GUI frame-buffer non-...
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1answer
171 views

Can gstreamer fbdevsink output to Xvfb virtual framebuffer? Which device to use?

I learned recently how to use Xvfb virtual Linux framebuffer: https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=261264 I want gstreamer fbdevsink output into a virtual framebuffer, but that ...
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1answer
152 views

Displaying a picture on the framebuffer while running a script created with dialog

I have setup scripts that use the dialog command. They are used to prepare embedded servers. I'd like to display a picture on a edge while a dialog script is running. The problem is, that dialog by ...
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0answers
345 views

Xfbdev not found after including X (tinyx/kdrive) in Buildroot

I'm trying to add Xorg to an evaluation board for which I've already been provided with a working linux kernel. The evaluation board has an LCD display and I can confirm hardware & drivers are ...
2
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1answer
817 views

How do I get fb0 scanline length?

I am accessing /dev/fb0, the screen's frame buffer, in console mode, Debian 10, using a HP Envy Touchsmart laptop, using fwrite standard C function. I read this page: https://techoverflow.net/2015/06/...
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0answers
373 views

How can I display graphics on the screen from the kernel over the top of my X11/Wayland session?

I want to draw simple (2D bitmapped) graphics onto my screen (in response to (simple) external inputs) with the lowest latency possible (the order of tens of milliseconds) so I can empirically test ...
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1answer
622 views

How can I prevent a TTY (e.g. /dev/tty1) from writing to the framebuffer (/dev/fb0)?

I'm running a Raspbian Buster server with no Xserver. I want to display wallpaper on a connected television but /dev/tty1 keeps over writing /dev/fb0 either with a blinking cursor or just refreshing ...
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1answer
181 views

How to prevent a particular terminal (e.g. /dev/tty1) from writing the cursor to framebuffer (e.g. /dev/fb0)

I'm running Raspbian Buster with no Xserver but attached to a television. I have a script that writes an image to the framebuffer from a timed systemd service. The problem is /dev/tty1 is writing ...
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0answers
329 views

How to set a large stty size?(default 80x24)

I'm really not sure where is the problem, so I'm putting all message i think helpful here. dmesg | grep drm [ 0.316388] fb0: switching to cirrusdrmfb from EFI VGA [ 0.316769] [drm] fb mappable ...
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0answers
551 views

Struggling with display KMS options on Lenovo D330-10igm

I'm trying to replace the default Windows 10 installation with Linux on this hybrid tablet. What I tried First I tried with Ubuntu 18.04, blank screen, I thought about starting modifying the KMS ...
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0answers
166 views

Accessing the full screen in console mode

I have a newly installed version Rockchip Debian running on a Libre Computer Renegade that I use solely in console mode. I am trying to get text to take up the entire screen and have managed to ...
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0answers
131 views

Redirect all keyboard input to a detached screen session

I'm trying to build a headless system using a Raspberry Pi; I have two programs runnning on it, one to catch all the input from a barcode reader (a simple keyboard emulation device) and one to display ...
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0answers
192 views

How do I vsync in bash (or the Linux framebuffer)?

I was trying to see how fast I could fill/swap on /dev/fb0 with something to the effect of: while :; do head -c $SIZE /dev/erg > /dev/fb0; head -c $SIZE /dev/zero > /dev/fb0; done (Where /dev/...
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0answers
64 views

Display blacking out on boot (Macbook Linux)

(Please note that I am breaking this out as a separate question from this one I asked earlier: How exactly do the Linux display device files work?) I have a Linux From Scratch system that I've built (...
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0answers
177 views

How exactly do the Linux display device files work? [closed]

I don't really understand how the Linux display device files work and interact together. What files in the /dev tree need to go where and where do they need to connect/point to, in order to show a ...
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1answer
833 views

mapping linux /dev/fb0 to DDR for displaying

I want to write a linux driver which maps my specified memory address space to /dev/fb0. the driver should be specified by what part of linux? drm or frame buffer or server X or somthing else? Which ...
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1answer
237 views

Two screens/monitors in Linux console (FB not Xorg)

I try to 'mirror' a Linux console (not Xserver) from a Dell laptop to an external monitor connected with HDMI cable. The graphic card is Intel UHD 620. What's the best approach? Initial net search ...
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1answer
303 views

Kernel Feature needed to change framebuffer colors?

I'm trying to change the colors in the virtual terminal. So far I've tried: echo -en "\e]PXYYYYYY"-style escapes writing to /sys/module/vt/parameters/default{red,grn,blu} the PIO_CMAP ioctl At this ...
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1answer
2k views

How to display an X11 screen from a remote machine? (Alternative to ssh -X)

I am locally on a machine without root rights. X forwarding is disabled. Remotely I am running a process on a machine without a screen, using the Xvfb virtual framebuffer which simulates an X server ...
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0answers
144 views

Modify start up routine of LXDE using startx command

I have built lxde and fbtft driver for Raspberry Pi using Yocto. In order to correctly start X11 session and dbus, I need to stop the existing one and execute something like: FRAMEBUFFER=/dev/fb1 ...
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0answers
288 views

Embedded linux - USB framebuffer device mounting

I have a embedded system which consists of a usb framebuffer display, and a customized embedded linux (3.10.59) box running Busybox (1.21.1). There is software running a application which utilizes ...
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2answers
7k views

How to send commands to fbi over SSH?

I'm using fbi to display some images. fbi has some keyboard controls, like +, -, Page Up, Page Down, etc. to control the images. Instead of using keyboard, I want to send these control commands over ...
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0answers
2k views

How can I run (start) a framebuffer application via SSH?

I am currently fiddling around with a RaspberryPi and a TFT hat. It is connected to the RPi GPIO pins. The TFT screen itself is working and I see the normal Linux console on it. I fetched a quick ...
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1answer
10k views

How can I get my framebuffer console working?

I have an Apple MacBook that is running a Linux From Scratch system that I have built. It is a minimal system, just booting into a bash prompt, with no X Window System installed. The graphics chip is ...
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1answer
433 views

Do I need a framebuffer driver for a minimal CLI system without X?

I've recently built a Linux From Scratch system on my Apple Macbook laptop; however, I've been struggling to understand the graphics hardware and what kernel driver options I need to enable. The LFS ...
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1answer
4k views

Is there a way to add margin, border, offset or padding to the Linux frame buffer text console to compensate for HDMI overscan?

I have a newly bought cheap 8 inch TFT LCD display that is "cutting the edges off" on all sides (i.e., not showing all the pixels). I've come to understand that this is due to "overscan" which seems ...
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1answer
1k views

How do i set framebuffer console font > 32x16?

I need a to set a font larger than 32x16 for my framebuffer console. As far as i know 32 is the maximum you can do. Is there a workaround? I'm fine with starting an alternate framebuffer terminal (...
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1answer
321 views

Linux framebuffer not reverting to text console when netsurf crashes

On an older computer running Linux (using vesafb, musl libc, busybox), Netsurf will occasionally segfault in low memory situations. When it does so, the last image stays visible on the display, and ...