Dave, Thank you for your reply, which I found both enlightening and informative. This will also help me explain to others.
On 15/12/2023 17:04, Dave Mielke wrote:
Disabling the brltty service doesn't prevent it from being automatically started by a USB udev rule. If you really don't want a Systemd unit to start then you need to systemctl mask it.
I haven't heard of masking a service. To me disabled, means disabled, i.e no longer active or able to affect the system. However, having read up on it I see it is a 'stronger' version of disable. Thank you for pointing that out.
I hope it's okay for me to point out that Arduino and friends are just as much to blame as brltty is. Brltty's problem is that some braille device manufacturers don't bother customizing their USB vendor and product IDs. Yes, they should do it. Also, however, so should Arduino and friends be doing exactly the same thing. There'll always be such conflicts as long as whomever doesn't stop using generic vendor/product IDs.
I am wanting to better understand so its no problem at all. As far as I know, Arduino does customize its vendor and product IDs. Genuine boards should be appropriately identified. The problem is that there are a multitude of clone boards around, mostly from Far East sources which use generic UART chips and generic IDs. There are also boards from Adafruit, Sparkfun, STM and others. Not sure how good they are at customizing their product IDs. There are also many products from other vendors that have generic chips so I guess this is always going to be a problem. I had imagined that there ought to be some way of managing access to devices in udev or by detecting known Braille devices, but with all those devices with generic IDs about I can now see that this is not so straightforward.
Can you suggest a way to design it that way? Since you expect it to be that way, you must have some idea regarding how to do it that way. A braille user would be unable to make such a choice without first being able to read his/her screen, which means, yes, that his/her braille deivce must already be working. Let's call it one of those "catch 22" situations.
You make a good point here which I failed to appreciate. I would not imagine Braille user being able to install a Linux system for various reasons, for example not being able to see the BIOS messages or knowing when the system has actually finished booting, but if having brltty built into the distro makes that possible, then I absolutely support that. I had also imagined that if a Braille user can open, read and edit a document, that they ought to be able to respond to a prompt, but how could they do so if the software that enables this is not yet in place? It makes sense to have it already right there, in the distro. I guess everyone else just needs to be aware of it and learn how to disable it appropriately when its not needed.
If it's earlier than 6.5 then your distribution is too old. As of brltty-6.5, we split our USB rules into two - generic and customized. So, all you really need to do is to ensure that you're at least at brltty-6.5 and then to uninstall the generic USB rules package.
It looks like it is earlier than 6.5. I re-installed brltty from the repository and ran the brltty --version command as suggested and it returned version 6.4. My Linux Mint distro is up to date, but Mint is always behind Ubuntu/Debian in terms of the software package versions in the repository. I am therefore not surprised. -- John.
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