Re: 0bda:b812 USB "3.0" WLAN devices only report a maximum of 480 Mbps

[Fabian Melzow <fabian.melzow@gmail.com>]

Am Sun, 5 Nov 2023 21:10:47 -0500
schrieb Alan Stern <stern@rowland.harvard.edu>:

> On Sun, Nov 05, 2023 at 09:06:16PM +0100, Fabian Melzow wrote:
> > Am Sun, 5 Nov 2023 14:16:18 -0500
> > schrieb Alan Stern <stern@rowland.harvard.edu>:
> >   
> > > Have you tried plugging the device into a system running a
> > > different OS (Windows or MacOS-X)?  Or even a different Linux
> > > system?  
> > 
> > Yes, I also made a short test with the lsusb of an old Debian 11
> > Live-DVD. I got these devices for testing from the Amazon Vine
> > program and after the third Monday-Hardware WLAN-device with the
> > same problem I thought I should report this problem, to maybe help
> > real users.  
> 
> A test with Windows might be more informative, if you can manage to
> do one.  Perhaps the Windows driver knows how to configure the device
> to run at higher speed.
>
> Also, curiously enough, when I did a web search for reports of
> problems with this chip, the vast majority of messages were about it
> not working with Linux at all because Debian/Ubuntu did not include
> sufficiently up-to-date drivers.  People had to download driver
> source code from a github project and build and install it for
> themselves in order to get the device to function.  They didn't
> mention what speed it used on the USB bus.

The Linux rtw88 driver is maintained by Realtek and, if my searching is
right, first appeared in Linux 5.18, so it's a newer one. I could
trigger an Oops, which I also reported yesterday. According to
the Debian backport https://github.com/lwfinger/rtw88 some versions of
the chipset are still unsupported. 

The rwt8822bu driver has also a non-USB version rwt8822b, so the chip
for the USB support can also be separate from the main chip, but until
now don't want to destroy one of the plastic cases.

Fabian Melzow