Talking about OpenGL for
OpenCPN on Rpi is a bit confusing.
There seems to be 3 different variations of OpenGL available to
OpenCPN on the Rpi:
OpenGL On Presumably using the legacy driver.
Software OpenGL.
OpenGL On with experimental VC4 driver, either Fake or real KMS.
Some other points of confusion:
Memory Split: seems to only be relevant to the legacy driver. Eric Arnholt the author of the experimental VC4 driver says that it is not using the memory split. Seems that it uses CMA (continuous memory allocation) which is set to 256Mb on OpenPlotter. It seems that if using the experimental driver it might be beneficial to set the GPU memory to minimum (16Mb) to free up memory?
Screen Size: It might be useful if people mentioned the
screen size they are using.
I've been playing with a Rpi3b+ on our
boat for the last few months, and when it works it works very well. But, unfortunately there still seems to be a few problems.
I have a 1024*768 touchscreen
monitor.
Rpi 3b+ with open plotter updated.
kernel updated to latest 4.19.XX
The
network is configured as an Access-point and also sometimes shares an
internet connection from a Ubiquity Bullet connected by Ethernet.
I have Sean's
weather sensor connected by USB that feeds
wind and Barometric data.
Vesper
AIS currently connected by
WiFi; has also been connected by USB.
I have tried all the options for OpenGL:
Non OpenGL worked well but often became unresponsive after a day of use.
Software OpenGL caused the idle CPU usage to go up and the temperature warning symbol to appear on the screen; I could not detect much if any performance improvement over nonGL.
The experimental driver with fake KMS seems to
work the best, it is fast, has low CPU usage and seems to cause the least amount of hang-ups. Sometimes the screen freezes, but the rest of the system continues to
work.
I occasionally see errors in dmesg something like "VC4 failed to allocate XXXXX bytes CMA buffer".
The system seems to like to fail at the worst times, there have been a few hang-ups just as we are entering a harbor after running all day without a hitch. I run a second OpenCPN setup on a Windows10 computer so I can instantly switch over; Never a hiccup on that system.
The
AIS on the Rpi is not the same as on Windows, I do not see the CPA graphics on the Rpi.
I'd like to see this working, so any suggestions about how to help de-bug it would be appreciated.