I recently got my hands on what as far as I can tell is an MSP3520 Display: http://www.lcdwiki.com/3.5inch_SPI_Modu ... KU:MSP3520
After some time of looking around various resources I found that existing drivers would: not compile/are intended for older versions of the rpi linux, are intended for 32 bit installs, or are designed for an SPI controller sitting in front of the ili9488 using it in a non SPI configuration.
I would like note before getting into this:
I'm fairly inexperienced (Never touched the Linux kernel in my life). Though I am trying to do my due diligence in reading how the fb drm crtc stack works, its a lot of information to process.
I found this thread containing someone going through similar issues but I couldn't figure out how they got it working viewtopic.php?t=355870
I started writing my own driver but I'm currently having two issues:
1. The screen is visible during boot (RPI logo) but as soon as get to the OS fully booted I'm not able to interface with the screen.
2. fbset is reporting some interesting rgba configuration
Here some base test thingsAnyone would be interested in reading the the exact process I'm using I currently outlined it here: https://github.com/Vasily-Kapustin/ti9488
I'm lost and in over my head
If anyone has any pointers to what I'm doing wrong I would greatly appreciate the help. I can hopefully post more in-depth information related to the problem if required though please be specific in what command / files to use bc I'm new to this.
[UPDATE]
Using the drm.debug=0x14 option in the /boot/cmdline.txt is very useful
switching to vc4-fkms-v3d I can now write to the framebuffer! Sadly my VNC doesn't work with this option
switching to remove both vc4-kms-v3d and vc4-fkms-v3d results in the desktop show on the screen (I don't want this).
Will investigate further
After some time of looking around various resources I found that existing drivers would: not compile/are intended for older versions of the rpi linux, are intended for 32 bit installs, or are designed for an SPI controller sitting in front of the ili9488 using it in a non SPI configuration.
I would like note before getting into this:
I'm fairly inexperienced (Never touched the Linux kernel in my life). Though I am trying to do my due diligence in reading how the fb drm crtc stack works, its a lot of information to process.
I found this thread containing someone going through similar issues but I couldn't figure out how they got it working viewtopic.php?t=355870
I started writing my own driver but I'm currently having two issues:
1. The screen is visible during boot (RPI logo) but as soon as get to the OS fully booted I'm not able to interface with the screen.
2. fbset is reporting some interesting rgba configuration
Here some base test things
Code:
pi@raspberrypi:~ $ fbsetmode "480x320" geometry 480 320 480 320 24 timings 0 0 0 0 0 0 0 accel true rgba 8/16,8/8,8/0,0/0endmodesudo cat /sys/kernel/debug/dri/2/stateplane[32]: plane-0crtc=(null)fb=0crtc-pos=480x320+0+0src-pos=480.000000x320.000000+0.000000+0.000000rotation=1normalized-zpos=0color-encoding=ITU-R BT.601 YCbCrcolor-range=YCbCr limited rangecrtc[34]: crtc-0enable=0active=0self_refresh_active=0planes_changed=0mode_changed=0active_changed=0connectors_changed=0color_mgmt_changed=0plane_mask=0connector_mask=0encoder_mask=0mode: "": 0 0 0 0 0 0 0 0 0 0 0x0 0x0connector[31]: SPI-1crtc=(null)self_refresh_aware=0max_requested_bpc=0pi@raspberrypi:~ $ cat /dev/urandom > /dev/fb0cat: write error: No space left on deviceI'm lost and in over my head
If anyone has any pointers to what I'm doing wrong I would greatly appreciate the help. I can hopefully post more in-depth information related to the problem if required though please be specific in what command / files to use bc I'm new to this.
[UPDATE]
Using the drm.debug=0x14 option in the /boot/cmdline.txt is very useful
switching to vc4-fkms-v3d I can now write to the framebuffer! Sadly my VNC doesn't work with this option
switching to remove both vc4-kms-v3d and vc4-fkms-v3d results in the desktop show on the screen (I don't want this).
Will investigate further
Statistics: Posted by VasilyK — Mon Apr 15, 2024 8:55 pm — Replies 0 — Views 33