Running koreader on the Raspberry Pi + Eink display

[kirillyatsenko]

Hello,

As I understand from the following documentation:
https://github.com/koreader/koreader...doc/Porting.md
The koreader requires the framebuffer driver to be present on the system, is it right?

I'm planning to use raspberry pi for my project + eink display.
However, I couldn't find any eink display that is already supported by the kernel or any out of tree drivers for it.

The display that I'm planning to use:
https://www.good-display.com/product/386.html

So, the steps are:
1. Implement framebuffer eink driver (SPI)
2. Point koreader to use the framebuffer device
3. Enjoy

Are the steps correct, or I'm missing something?

Maybe someone has already done it?

[pazos]

It sounds like a very bad idea. For much less money you could get a real device that has:

a 10x better screen (I would say 1000% better )
with frontlight
and touchscreen
a PMIC and battery
linux kernel support for all those things.
it is already supported in KOReader

Buuut if it is just for the fun and you want to waste a little money and much time, you'll need a bunch of things missing on your steps, including

- write a new device abstraction for your particular device (sdl works on computers with a desktop environment or on EGL surfaces, both work on the pi, but not your thing)
- write the output module that interfaces with your kernel driver)
- create some sort of input, write the input module

And a bunch of other things.

If you want to play with a Pi it is better to skip those sh***y eink screens and get yourself a 7" touchscreen display, where both input and output should work almost out of the box with the SDL version of KOReader (arm64, if possible) even without Wayland/X

[kirillyatsenko]

Hello Pazos,

Thanks for the reply.

Yes, I'm totally agree with all of your points.

However, I want to build the reader as a hobby.
I have some experience with linux, and want to learn PCB design.

I like this project:
https://hackaday.io/project/192688-the-open-book

However, it's not a linux device, so it not easy to use existing tools.
I want to do the similar project, but on linux.

I see that there is a generic framebuffer support, can I use it in my case?
https://github.com/koreader/koreader...fer_einkfb.lua

Regarding the SDL, I dont have much experience with it, but of course I can learn it.

The SDL module should be written as part of the koreader or as part of the linux in general. This part I dont really understand clearly. Do you have some examples maybe?

Thanks!

[kirillyatsenko]

Originally Posted by pazos

It sounds like a very bad idea. For much less money you could get a real device that has:

a 10x better screen (I would say 1000% better )
with frontlight
and touchscreen
a PMIC and battery
linux kernel support for all those things.
it is already supported in KOReader

Buuut if it is just for the fun and you want to waste a little money and much time, you'll need a bunch of things missing on your steps, including

- write a new device abstraction for your particular device (sdl works on computers with a desktop environment or on EGL surfaces, both work on the pi, but not your thing)
- write the output module that interfaces with your kernel driver)
- create some sort of input, write the input module

And a bunch of other things.

If you want to play with a Pi it is better to skip those sh***y eink screens and get yourself a 7" touchscreen display, where both input and output should work almost out of the box with the SDL version of KOReader (arm64, if possible) even without Wayland/X

If you have time, please answer

[pazos]

Hi. It is still a very bad idea.

If you want to play with PCB design just replicate the openbook device/firmware. It should be way easier and more fun.

If you want to play with KOReader just get a device where it works for the most part and fix the platform bugs that still remain (ie: pocketbook).

If you want to play with a RPI and a shitty Eink display just get them and play with easy stuff: learn to draw text and images to screen, the different refresh modes. Figure out a proper way to use the thing without KOReader as the main purpose.

Then, once you master your "device" you can write a proper port to KOReader.

It will suck because KO is meant to be used with a touchscreen or a pointer device.
It will suck because KO wasn't never actively tested with resolutions below 800x600
It will suck for many, many reasons.

And, on top of that, you won't get any kind of support during the port. Even if/when the port is done it is unlikely to be maintained upstream because there's no device to maintain.

[pazos]

Originally Posted by kirillyatsenko

I see that there is a generic framebuffer support, can I use it in my case?
https://github.com/koreader/koreader...fer_einkfb.lua

Regarding the SDL, I dont have much experience with it, but of course I can learn it.

The SDL module should be written as part of the koreader or as part of the linux in general. This part I dont really understand clearly. Do you have some examples maybe?

Thanks!

sdl is a library that we use as an abstraction for regular computers. Non sdl targets (kobo, kindle, remarkable, android, cervantes, pocketbook..) use their own input/output modules.

You'll need to write your own input/output modules for your device. So, nope you cannot repurpose the HAL of other devices as is. You can read it and understand it to be able to figure out the things expected to be done by those modules, so you can implement the things for your own.

Google is your friend, generic questions not welcome

[Quoth]

Originally Posted by kirillyatsenko

Are the steps correct, or I'm missing something?

Yes, it's a panel used for retail labels.
Unless you are developing a new retail label this is pointless, and if you are the Raspberry Pi is the wrong platform.

What @pazos writes is a 100% true.