Hello . I'm interested in what modems today are approaching the concept of libre (FSF)?
If I'm not mistaken today there is not a single free modem, they all have proprietary firmware.
V.92bis 'might' fullfill that criteria, perhaps some mISDN adapters as well.
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Disclaimer: I don't subscribe to the FSF's point of view that a big firmware blob hidden from view (and unchangeably stored in on-device flash) would be magically better than the same blob uploaded by the driver into on-device RAM.
AFAIK, the "openness" of Qualcomm SoCs used in any of these modems is limited to the ARM core(s). No one knows what goes on in the hexagon cores, which is really the interesting part. I'd like to emphasize this quote from the link you posted:
Not everything is open in this firmware. The baseband firmware, aka the RF bits known as ADSP firmware, remains closed and not yet reverse-engineered by anyone
Sufficiently complex hardware is closed. And today, such "hardware" is mostly firmware running on more or less generic processors. The old concept of task specific peripherals with a few registers controlling the behaviour just doesn't exist anymore. Your GPU, WiFi controller, LTE modem, SSD controller etc are all pretty much the same thing: Processor cores, RAM, flash and firmware. The firmware is what makes it different, and is where most of the development budget was used.
@bmork Thank you very much for the detailed answer.
Okay, I'll ask differently. I indicated two options that today are considered the most free, so to speak, they are used in Librem5 and Pinephone Pro
Is there something better in your opinion?
I think that you understand, if you install a free FSF distro ( Parabola,Trisquel etc) on non-free hardware, then it is useless. Therefore, iron is the most important in this chain