5" Compatible displays.

djw0bbl3

Hi there, super awesome community!

I am just interested to know whether there are any known displays of size ₅" that are compatible with Emteria OS on the Raspberry Pi. I understand that the 52Pi 5" touchscreen is a listed compatible screen, but I was hoping for something that is connectable to the pi via a ribbon cable instead of hdmi+usb.

Thanks 🙂

IKS

We didn't test any other DSI screens. Please feel free to test it yourself, if you wish. From the perspective of the OS itself, it is only a matter of configuration.

djw0bbl3

Thank you very much for the reply. I would like to follow through with this task, but I am a little unsure of the configuration steps that are required. I am not so much a beginner when it comes to Linux, but could you maybe provide me with a couple of steps to follow? I would very much appreciate it.

Do you think a display solution like this would be a good choice?

https://www.dfrobot.com/product-1784.html

It doesn't seem as though their are any required driver installs during their installation tutorial for it on Raspbian... does this mean that they are already in the kernel?

Finally extremely impressed with the ease at which I was able to install the OS on the Pi and start making modifications once I was booted. Awesome work :smile:

IKS

I would give this touchscreen a try, I don't see any reason why it shouldn't work out-of-the box. If it doesn't though, you should go ahead and setup a UART console for kernel logging and a shell (https://www.raspberrypi.org/documentation/configuration/uart.md).

djw0bbl3

Hi Igor, Thank you very much for the response. I think I will go ahead and order the part, as it fits the specifications for what I want out of the design. Thank you also for referring me to this documentation, hopefully their shouldn't be an issue with the setup, but if their is you've given me a place to start! Thank you very much, I will keep you posted on progress :smile: Enjoy your Monday!

P.S. I was taking a look at your involvement in DARPA, I hope you don't mind. Super awesome, and well done on the project :smile:

djw0bbl3

Hi again, Unfortunately I have some bad news. The DFRobot display listed above is no longer in stock, so I won't be able to order it for the project. A real kick in the teeth to be honest.

This is an issue for me as I have a lot of different things to pull together for the project to be a success. I also have a limited budget, so I am unable to purchase several display components for testing.

Are there any currently unsupported display components that you could recommend I could try out? If not, what do you think I should be looking for with regards to features/drivers that such a display would have to show some promise for functionality after some development?

I hope this all goes well as it is my degree project, and I am really hoping to get a well working device in the next few months. Fingers crossed! Thanks for the help,

IKS

Sorry, we don't have any experience with displays other than listed in our help article (https://help.emteria.com/kb/devices-rpi-3). So for now it is only one 5" screen: 52Pi.

djw0bbl3

No Problem! I have a further development and I am going to try and configure a Pimoroni HyperPixel 4.0 display (https://shop.pimoroni.com/products/hyperpixel-4?variant=12569485443155&gclid=Cj0KCQiAzKnjBRDPARIsAKxfTRDiECuaDbVTgmJdw0Q3JzmmSMMz5B27Eh5hy2KTdpaEnxjz8w6SZFUaArISEALw_wcB#description) which features a GT911 touch IC. I was pointed towards this github page by a contact I have made over at Pimoroni (https://github.com/goodix/gt9xx_driver_android/blob/master/documents/Potring_Guide.md). If you see the Porting-Guide.md, it suggests adding the included driver files to $(KER_SRC)/drivers/input/touchscreen/. However I cannot find this within the Emteria Android FS. Do you know what would be the best way forward would be to follow this guide?

Once again thanks for the help,

djw0bbl3

Also it might be worth adding that I have direct contact with the software developers over at Pimoroni. I think it would be great for the Emteria Platform if we could get this display supported! :smile:

IKS

I think you will need to rebuild the kernel in order to add those drivers. We are currenlty preparing the release of our RPi kernel to a public repository. In the meantime, you could use this one to test the integration & compilation: https://github.com/android-rpi/kernel_rpi

djw0bbl3

Been fooling around all morning trying to find a kernel to use for this! Thank you very much for pointing me to this, didn't seem to get a forum notification. I am making progress and hope to have the driver installed for when the display arrives. Many thanks, enjoy your weekend.

djw0bbl3

Which toolchain do you advise to use for building the kernel? downloaded the latest ndk but its missing GCC in the toolchain... not sure how to proceed on this. Any help would be appreciated!

djw0bbl3

I have the kernel compiling at the moment... had it run through but stupidly didn't select the goodix driver in the config menu before compiling... also I am right in saying that Emteria is 32-bit? If this is to be successful I am confident that the touch IC will function correctly... however I am unsure whether there is a seperate device driver that handles the display functionality? Do you have any idea about this?

Thanks for all the help, been extremely helpful.

djw0bbl3

So I had it compile successfully which is great! But I noticed that a loadable .ko had not been created, as I did not select the GT9XX driver with an 'm' symbol. So I started again but the config refused to let me... only letting me include it with a "*". so I edited the created .config for it as a module, but then I got this error: warning: symbol value 'm' invalid for TOUCHSCREEN_GT9XX

It restarted the config and gave me only a y/n option, not the required 'm' for the .ko I wanted to create and load to the pi.

Do you know why this might be the case? Is there any way I can make it a .ko?

Thanks,

djw0bbl3

Apologies for the questions but as this seems to be an "included" driver rather than a loadable .ko, could I just go ahead and replace the kernel? If so, is there a specific .config I could use to ensure that all the necessary libraries and drivers are installed when I compile the driver? Enjoy your weekend :smile:

IKS

Hey, thanks for the information. Yes, theoretically you should be able to replace the driver in your kernel, rebuilt and replace the kernel itself in the platform. I will let you know as soon as our rpi kernel is pushed to https://gitlab.com/emteria/public/os

djw0bbl3

Hi again, long time no speak. So I am still working with the module and I still have not had any breakthroughs. I have created a dtbo for the device using the dts file provided on their git "https://github.com/pimoroni/hyperpixel4" and I have the goodix driver installed... but I believe this is already preinstalled on emteria? I think the only thing missing now is the executable hyperpixel4-init (inside the dist directory of the drivers on the git). When I try to execute it on android with ./hyperpixel4-init I just get bcm2835_init: Unable to open /dev/mem: No such file or directory. Is this because I have not compiled it with the android ndk cross compiler? Is there a way I can do this? Any help would be very much appreciated as always!

P.S. When the module is connected all I get is the back-light turned on. Is there anything I can check within Emteria to see if it is being recognised in any way?

Thanks :smile:

IKS

Sorry, we were too busy with other task so far. For /dev/mem you'd need to enable kernel flags (don't remember the name).

djw0bbl3

That's not a problem! If you have any suggestions or ideas about how I can progress with the task I would love to hear. I've put quite a lot of work into this so it would be a shame to not be able to finish working on it and get it out to the community for use. I am most definitely going to keep pressing forward with it in the coming weeks. Is there any documentation you could point me to on the subject of kernel flags? Thanks once again for all the assistance provided! :smile:

djw0bbl3

Hi Kalkov, I am still working on this and I was reading online about a similar problem encountered `https://community.nxp.com/thread/450382'

Am I right in saying that /dev/mem presence is disabled in the kernel config? In this case would recompiling the kernel with it changed to present solve the problem?

Thanks,