Linux performance is unusable

[Artefact2]

For some reason, I am getting really bad performance when using the receiver (Holyiot 21017) on Linux. The number of ticks per second seems to be capped at around 200 globally, and a single tracker will not go above 100 ticks per second. With even just six trackers, tracking in game is too stuttery to be useable.

I am running the firmware from main branch with workaround from #31.

Here are captures of the same trackers and receiver, running the same firmware, on Windows:

2025-12-30_16-11-11.mp4

And on Linux:

2025-12-30_16-14-29.mp4

Can anyone else reproduce the same issue?

Here is the contents of /sys/kernel/debug/usb/devices:

T:  Bus=05 Lev=01 Prnt=01 Port=02 Cnt=03 Dev#=  4 Spd=12   MxCh= 0
D:  Ver= 2.00 Cls=ef(misc ) Sub=02 Prot=01 MxPS=64 #Cfgs=  1
P:  Vendor=1209 ProdID=7690 Rev= 4.01
S:  Manufacturer=Holyiot
S:  Product=SlimeNRF Receiver Holyiot-21017
S:  SerialNumber=C152931BF8A72112
C:* #Ifs= 3 Cfg#= 1 Atr=c0 MxPwr=100mA
A:  FirstIf#= 0 IfCount= 2 Cls=02(comm.) Sub=02 Prot=00
I:* If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=00 Driver=cdc_acm
E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=10ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_acm
E:  Ad=82(I) Atr=02(Bulk) MxPS=  64 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS=  64 Ivl=0ms

[Artefact2]

Fixed by setting CONFIG_USB_HID_POLL_INTERVAL_MS=1 in prj.conf. The default value of 0 makes the Linux usbhid driver default to a poll interval of 125 Hz, which severely caps performance.

Maybe we should consider changing the default?