[BBAI-64] RPi Display 7-inch DSI

General Discussion
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1

Just wondering if anyone has tried a DSI display on the AI-64?

I’ve tried an Official 7-in RPi Display with a waveshare 15-to-22-pin DSI converter plus an external 5v power supply although haven’t yet managed to get an image.

I’m on latest software as of yesterday, just hoping someone could at least confirm they’ve seen a display function through the DSI Port.

Thanks, Mat

2

Hi @murc585 ,

Here’s a quick photo of how to wire this up… (RPi 7-inch is powered by USB…)

FULL

Use, BBAI64-DSI-RPi-7inch-panel.dtbo in /boot/firmware/extlinux/extlinux.conf

fdtoverlays /overlays/BBAI64-DSI-RPi-7inch-panel.dtbo

Regards,

3

If you don’t mind sharing, where did you find the adapter for the display. I looked and did not have much luck.

4

There are a few different clones…

Regards,

1 Like
5

Thanks for the help, I was able to get an image although with some artefacts:

  • The image seems offset horizontally to the right about 50 pixels and upwards vertical about 10 pixels.
  • There is a left/right pixel jitter (about 2 pixel wide)
  • My DisplayPort monitor repeats the low resolution of the DSI display (no dual display support)
  • the touch screen input does not seem to function

Have you experienced any of these? I tried different ribbon cables but I observe the same effect.
This is the adapter I’m using:
https://www.pishop.ca/product/compute-module-dsi-display-adapter-22pin-to-15pin/
image

6

ah fun! sorry i haven’t tired x on it yet… The offset does match my ‘console’ display, we need to tweak the raspberry pi, porch values…

Looks like TI tweaked these… https://git.beagleboard.org/beagleboard/linux/-/commit/e2c9db9a4cf898557164a53958c317fba034a885

Touch screen driver, sorry haven’t tested that yet. That driver has been fun on older BBB capes, might need to force it.

Regards,

7

Are these hard-coded in the source or can they be modified via config file?

8

I know this toppic is kinda old already, but im running into exactly the same problem with the image offset and the pixel jitter.

Do any of you guys find a solution for this problem or is the beaglebone-RPi Display combi just bad?

Regards,

9

Hello could you please share with us the BBAI64-DSI-RPi-7inch-panel.dts file ?

Many thanks,

10

Regards,

11

I’m having issues with the touchscreen inputs. I suspect it might be a driver issue. Any tips on where to get info on the driver or updates?

12

The touchscreen is via the ft5406, does it show up over i2c? src/arm64/overlays/k3-j721e-beagleboneai64-RPi-7inch-panel.dts · v5.10.x-ti-unified · BeagleBoard.org / BeagleBoard-DeviceTrees · GitLab

or does it show up under evdev?

Regards,

13

Thanks for the quick reply.

xinput -list output:
debian@BeagleBone:~$ xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ generic ft5x06 (00) id=6 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ gpio-keys id=7 [slave keyboard (3)]

xinput -list-props 6 output:
Device ‘generic ft5x06 (00)’:
Device Enabled (116): 1
Coordinate Transformation Matrix (117): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Calibration Matrix (248): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Calibration Matrix Default (249): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Send Events Modes Available (250): 1, 0
libinput Send Events Mode Enabled (251): 0, 0
libinput Send Events Mode Enabled Default (252): 0, 0
Device Node (253): “/dev/input/event0”
Device Product ID (254): 0, 0

and testing with evtest will give a single button press event, and shows the change in position based on tapping the screen, but no button release event.

It seems what’s missing is the button release event.

14

Hum… input: edt-ft5x06: Handle unreliable TOUCH_UP events · raspberrypi/linux@1ff56d8 · GitHub

okay… todo, backport RPI’s edt-ft5x06.c driver… History for drivers/input/touchscreen/edt-ft5x06.c - raspberrypi/linux · GitHub

Opened: BBAI-64: RPI 7-inch Touchscreen (backport RPI’s edt-ft5x06.c) (#101) · Issues · BeagleBoard.org / Latest-Images · GitLab in my todo…

Regards,

15

That’s great - thanks so much for looking into it.

Let me know if there is anything I can do to help.

16

Hi @Darren_Freed please test: build (#18299) · Jobs · Robert Nelson / ti-linux-kernel-dev · GitLab if you click download, you’ll get a zip file that includes a linux-image*.deb file you can install locally and reboot…

pretty clean backport of rpi’s 5.10.x tree: backport: edt-ft5x06.c from rpi-5.10.y (50b5d283) · Commits · Robert Nelson / ti-linux-kernel-dev · GitLab

Regards,

17

Awesome! Works as expected now. Thanks so much! And for all you do for this community!!!