SOLVED: Ubuntu Linux - Remote not found with serial

rpm1200 · Post by **rpm1200** » Fri Feb 19, 2021 11:11 am

Hey all,

I was pulling my hair out about this so I thought it might be helpful to post what happened on my Ubuntu system. I have Ubuntu 20.04.2 LTS with both Java 11 and Java 8 installed. I was trying to use RMIR v2.12.8 to download from a remote using a serial (not USB) interface I built for JP1.X. Under Remote, Interface, JP1.X Serial the only options were Auto-detect and Other. I got the same results trying Auto-detect or by entering /dev/ttyS0 (which is the serial port I was trying to use) in Other. The interface read and wrote successfully to the same remote using the same laptop/serial port when I booted to Windows 10 and ran RMIR there.

I found that Java 11 was set as the default Java version in Ubuntu. To correct that, I ran the following:

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sudo update-alternatives --config java

and selected Java 8 from the list. But I found that the setting change did not help - RMIR still did not detect the remote.

Simple solution - after I rebooted and tried RMIR again, I found that under Remote, Interface, JP1.X Serial there were options for /dev/ttyS0 through /dev/ttyS9 in addition to Auto-detect and Other. I left Auto-detect selected, then I was able to upload/download to/from the remote successfully.

Just wanted to post this in case it can help someone else out; if you have multiple Java versions on Linux, there is no need to uninstall versions other than 8. Instead, use update-alternatives to select Java 8 and then reboot.

Post by **mathdon** » Sat Feb 20, 2021 6:30 am

Do I understand from this that RMIR v2.12.8 does not work with Java 11 on Linux, at least for your system and interface? That to me is unexpected. Is it possible for you to post the rmaster.err file from a failed attempt to download your remote with Java 11? I would like to understand why this is happening.

Post by **The Robman** » Sat Feb 20, 2021 8:05 am

He's posting his solution, so he's explaining how he got RMIR v2.12.8 to work. The main fix being to do this:

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sudo update-alternatives --config java

but then the really important part is, you need to reboot in order for it to take effect.

Post by **mathdon** » Sat Feb 20, 2021 8:47 am

Rob, as rpm1200 finished with "Instead, use update-alternatives to select Java 8 and then reboot", I presume he is saying that he got RMIR v2.12.8 to work with Java 8. I am asking about it with Java 11.

Post by **The Robman** » Sat Feb 20, 2021 8:53 am

Ah, I see what you mean.

rpm1200 · Post by **rpm1200** » Tue Feb 23, 2021 8:09 pm

As of 2018, only Java 8 was supported for Linux per this thread: http://www.hifi-remote.com/forums/viewt ... p?t=101290

It's possible that limitation is not present anymore and it might work fine with Java 11 now. If that's the case, I don't mean to cause any confusion. I just wanted to share the steps that got RMIR working for me on Linux.

Post by **mathdon** » Wed Feb 24, 2021 3:55 am

rpm1200 wrote:As of 2018, only Java 8 was supported for Linux per this thread: http://www.hifi-remote.com/forums/viewt ... p?t=101290

You didn't read to the end of that thread. Its last post, still from 2018, says

All is working well now with java 10 and upload and download. All the problem was not knowing which port was which. Removed the added serial card so that won't happen again. Thanks to all.
A special thanks to yaworski for the java 10 fix.

The latest Java is Java 15 and RMIR has been tested with that, too, and works correctly.