Re-enable serial backend as default

[buha]

I'm going to stick to the opinion that serial backend should be enabled by default, originally expressed in #684

https://ez.analog.com/linux-software-drivers/f/q-a/590608/iio_info-fail-detect-ad-pqmon-sl/552301

https://ez.analog.com/sw-interface-tools/f/q-a/571152/no-serial-context-available-for-iio-oscilloscope-on-linux/497805

https://ez.analog.com/linux-software-drivers/f/q-a/565555/iio-oscillocope-build-ubuntu-18-04-6-lts/481391

https://ez.analog.com/microcontroller-no-os-drivers/f/q-a/540802/re-ad9371-zc706-no-os-application-generation/412093

https://ez.analog.com/linux-software-drivers/f/q-a/549449/libiio-questions/432018

https://ez.analog.com/microcontroller-no-os-drivers/f/q-a/571627/usrp-e312-ad9361---iio-oscilloscope-doesn-t-work/499466

https://ez.analog.com/linux-software-drivers/f/q-a/583047/libiio-connection/529193

https://ez.analog.com/microcontroller-no-os-drivers/f/q-a/570970/using-iio-oscilloscope-with-no-os-in-zcu102-fmcomms2/497764

https://ez.analog.com/linux-software-drivers/f/q-a/101597/need-help-linux-pc-connect-to-ad9361-and-meet-libiio-usb-backend-issue/302075

These are results from searching WITH_SERIAL_BACKEND on EngineerZone, I put links to results from 2 out of 7 pages! I think it's enough to prove the point.

[dNechita]

@buha thanks for putting together all these issues that users have encountered. They seem quite a lot and therefore I'm leaning toward enabling it by default.

[rgetz]

I'm confused - in the CI pipeline (which drives the releases):
LinuxBuilds ubuntu_20_04 : Features enabled : serial iiod-serial
LinuxBuilds ubuntu_22_04 : Features enabled : serial iiod-serial
LinuxBuilds fedora28 : Features enabled : serial iiod-serial
LinuxBuilds fedora34 : Features enabled : serial iiod-serial
LinuxBuilds debian_bullseye : Features enabled : serial iiod-serial
LinuxBuilds debian_bookworm : Features enabled : serial local iiod-serial
LinuxBuilds opensuse_15_4 : Features enabled : serial iiod-serial
LinuxBuilds centos_7 : Features enabled : iiod-serial / Features disabled: serial
MinGWBuilds MinGW_W64 : Features enabled : serial / Features disabled: iiod
WindowsBuilds VS2022 : Features enabled : serial / Features disabled: iiod
WindowsBuilds VS2019 : Features enabled : serial / Features disabled: iiod
macOSBuilds macOS_13_x64 : Features enabled : serial / Features disabled: iiod
macOSBuilds macOS_13_arm64 : Features enabled : serial / Features disabled: iiod

It's pretty clear in the readme_build how to enable things, and what is necessary - I think you are going to trade off a few "how do I enable serial" to many "what is, and how do I install libserial port?"

-Robin

[nunojsa]

It's pretty clear in the readme_build how to enable things, and what is necessary - I think you are going to trade off a few "how do I enable serial" to many "what is, and how do I install libserial port?"

Agreed!

[buha]

I thought about that too, but it's so much easier to add a line to:

analog@precision:~$ sudo apt-get install libxml2-dev libzstd-dev bison flex libcdk5-dev cmake

to become:

analog@precision:~$ sudo apt-get install libxml2-dev libzstd-dev bison flex libcdk5-dev cmake libserialport

...than it is to explain that if you want to use libiio with libserialport, you gotta install this optional library, rebuild and reinstall with this or that flag enabled.

In theory the info it's all there. In practice it didn't play out well. Idk... maybe some colors, bold fond, some arrows would help users to get the info, But at this point I think of all the effort that went into those EZ investigations and it seems so pointless and avoidable.

[rgetz]

to become:

analog@precision:~$ sudo apt-get install libxml2-dev libzstd-dev bison flex libcdk5-dev cmake libserialport

That's actually the problem - it's called different names on different distributions - plus on most you need the -dev version.

Although - it should be easy to by default just look for it, if it can't find it - ignore, build without, and if it can find it - use it.