[clug] Bluetooth Mouse Lag

Scott Ferguson scott.ferguson.clug at gmail.com
Sat Aug 27 10:03:40 UTC 2016


On 27/08/16 14:19, Brett Worth wrote:
> On 27/08/16 13:31, Scott Ferguson wrote:
>> If I was you I'd examine the module options with 'modinfo'. You might
>> also consider telling us which module is in use :)
> Here's the modinfo on the Broadcom module:
> # modinfo btbcm
> filename:       /lib/modules/4.4.0-34-generic/kernel/drivers/bluetooth/btbcm.ko
> license:        GPL
> version:        0.1
> description:    Bluetooth support for Broadcom devices ver 0.1
> author:         Marcel Holtmann <marcel at holtmann.org>
> srcversion:     7D407A503FFEAA8C872B3E9
> depends:        bluetooth
> intree:         Y
> vermagic:       4.4.0-34-generic SMP mod_unload modversions
> It looks like it doesn't take options.


> Brett

This is a common problem with Linux - the developers can only code
support for what they can test, and many manufacturers make a number of
variants for their hardware. So in some cases e.g. Realtek you need to
tweak the code to support the variant under Linux, which may require you
to sniff the device when it's running under Windows (as I've had to do
with some USB devices) or decompile the Windows drivers, as others have
done with Bluetooth devices - extract the relevant hex (HCD) and use it
to rebuild the Linux driver*1.
In one case that I know of the only solution to music stutter when
moving away from very close proximity to the Bluetooth device was to
change the pairing code to 000 - i.e. just crap code that applied
equally to all OS.

Unfortunately I can offer you very limited help as I don't have access
to an identical laptop (of which there are a number of variants*2) - and
I'm (very much) *not* a gun device driver coder.

In your position I'd use Wireshark*3 to try and diagnose the condition -
but if your problems don't occur when Windows under identical conditions
I'd look to driver differences (between the Linux driver and the OEM
Windows driver). If it occurs with both Windows and Linux you may need
to enhance the reception - e.g. with an ACER netbook I had to add (hack)
an external WiFi aerial to get decent range without having to face the
screen at the AP (due to the case shielding the signal).

I'd be greatly surprised if you're the only one to experience the
problem and search for a solution.

One of the results from this query 'may' be useful:-


*2 https://wiki.archlinux.org/index.php/Dell_XPS_15

*3 https://wiki.wireshark.org/CaptureSetup/Bluetooth

Kind regards

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