On Fri, 17 Jul 2020 at 17:15, Ed Greshko ed.greshko@greshko.com wrote:
On 2020-07-18 03:59, Paul Smith wrote:
On Fri, Jul 17, 2020 at 7:14 PM Samuel Sieb samuel@sieb.net wrote:
I would like to buy a cheap Bluetooth receiver/transmitter for my desktop computer running Fedora 32. I have searched eBay for that, but meanwhile learned that most of them do not work on Linux. So, could you please advise me on that?
Where did you see that most don't work? I think it's the opposite. As far as I know, they all work. It's USB wifi devices that you're more likely to have trouble with (at least 5GHz ones). I recently needed a bluetooth dongle for BLE and picked one of the cheaper ones I could find and it just worked.
Thanks, Samuel and George. I found issues of compatibility with Linux at:
https://www.thetechlounge.com/best-bluetooth-adapter/
Meanwhile, I bought the following Bluetooth dongle, which was very cheap and therefore the risk is low:
Well, I was like Samuel and thought that all BT dongles work fine under Linux.
However, I just bought one to replace a failed device. It is a newer model which is marked CSR 5 in support of BT version 5. It fails to be recognized by bluez as adapter.
CSR https://en.wikipedia.org/wiki/CSR_(company) was formerly Cambridge Silicon Radio, now owned by Qualcomm and qualified under the name "Qualcomm Technologies International, Ltd. (QTIL)". It may not be easy to see technical documentation:
Qualcomm Technologies International, Ltd. Confidential and Proprietary - Qualcomm Technologies International, Ltd. (formerly known as Cambridge Silicon Radio Ltd.) NO PUBLIC DISCLOSURE PERMITTED: Please report postings of this document on public servers or websites to: DocCtrlAgent@qualcomm.com. Restricted Distribution: Not to be distributed to anyone who is not an employee of either ...
Did the packaging have the bluetooth logo https://www.bluetooth.com/develop-with-bluetooth/marketing-branding/? To get the logo your device has to pass the Bluetooth Qualification Process. Can you find your device https://launchstudio.bluetooth.com/Listings/Search? I did find https://launchstudio.bluetooth.com/ListingDetails/48853.
btmon shows...
HCI Event: Command Complete (0x0e) plen 6 #62 [hci0]
12.841706 Delete Stored Link Key (0x03|0x0012) ncmd 1 Status: Unsupported Feature or Parameter Value (0x11) Num keys: 0
BT has lots of features, you may be able to configure around this or your device may need "quirks" support in a driver.
So, I would stay away from Version 5 products for the time being.
Side note: The bluez maintainers didn't respond to my query about support for this adapter. :-(
From a youtube comment: "I bought some generic CSR V5, and my PC detected them, but they would not connect to any devices. All 5 of them don't work."
Some cheap USB rf devices were designed to be bundled with a particular external device (keyboard, mouse, headphone, etc) and lack capabilities expected from a general purpose device.
I expect the maintainers have enough work just keeping up with requests from manufacturers. One way to get their attention is to send them a couple devices, but I doubt they are interested in devices that weren't qualified.
Try a USB 2 port -- some bt5 dongles don't work with USB 3 ports (not surprising, due to the RF interference problems of USB 3).
-- George N. White III