How to add function to the display module or write one of my own

Peewe · 05-18-2017, 04:08 AM

Hello everyone,
I'm trying to interact with the GPU in order to write directly to the screen.
After a log research, the best ( I'm not saying the easiest ) way to do it is by Linux Kernel Modules. I'm trying to find out if I can find the module that interact with the GPU and modify it do to more things I want.
If I can't modify it I would like to know what I need to do in order to write such module. I didn't understand the following things :
1. Can 2 modules interact with the same HW ?
2. Is it depend on my GPU or I can write generic function ?
3. What are the steps I need to know in order to make such module to work ?

I'm not trying to make complicated thing .. just to write some pixels to the screen, but because some other reasons I need it to be from the kernel mode as a module.

My machine : I just install Ubuntu 64bit in Dual Boot with Windows 10
I have i7-6700 with Intel Graphics 530

If there is something unclear pls feel free to ask me. Thank you all and have a nice day

pan64 · 05-18-2017, 04:20 AM

the device driver is used to send "general" commands to the device, like draw a line/box/circle.
The driver is responsible to translate this message to something usable on the device. That's why the device driver itself is hardware dependend.
The existing video drivers are really complex and really hard to add anything (and without knowing the hardware itself).
Usually only one driver is used to drive a device.
I would say such kind of generic functions are already available, you only need to use them.

Peewe · 05-18-2017, 04:23 AM

Quote:

Originally Posted by pan64

the device driver is used to send "general" commands to the device, like draw a line/box/circle.
The driver is responsible to translate this message to something usable on the device. That's why the device driver itself is hardware dependend.
The existing video drivers are really complex and really hard to add anything (and without knowing the hardware itself).
Usually only one driver is used to drive a device.
I would say such kind of generic functions are already available, you only need to use them.

So if I want to display some pixels on the screen, how do I write the module which does it ? or should I write a device ? or I can edit the device driver which say to the GPU what to write..

pan64 · 05-18-2017, 04:33 AM

a device is a piece of hardware (for example a video card), actually which works, do the real job (=draws and displays the result).
You won't be able to modify the driver of your intel card (at least I think).
Probably you need to check this: https://en.wikipedia.org/wiki/Direct...Infrastructure

Peewe · 05-18-2017, 04:37 AM

Quote:

Originally Posted by pan64

a device is a piece of hardware (for example a video card), actually which works, do the real job (=draws and displays the result).
You won't be able to modify the driver of your intel card (at least I think).
Probably you need to check this: https://en.wikipedia.org/wiki/Direct...Infrastructure

Thanks for your answer ! As far as I know, It's possible I talked with someone who done it but I can't find him.
He told me to look at Linux Kernel Modules which lead me to the thread and now I'm trying to do what he has done.
I think I'll wait for more answers, but thank you

pan64 · 05-18-2017, 04:41 AM

Yes, that is definitely possible, the device drivers are written by human beings. But actually they know about this much more than me.