added fix for lagging btusb

content/Linux/Fixing lagging USB Headphones.md

@@ -0,0 +1,38 @@
+When receiving messages like this:
+
+```shell
+Bluetooth: hci0: ACL packet for unknown connection handle 256
+```
+
+Create `/etc/modprobe.d/disable_btusb_autosuspend.conf` with following content:
+
+```shell
+# Disable autosuspend for btusb to make the bluetooth keyboard work again
+options btusb enable_autosuspend=n
+```
+
+Then run 
+
+```shell
+mkinitcpio -P
+```
+
+Reboot and debug with 
+
+```shell
+$ systool -v -m btusb | grep autosuspend
+	enable_autosuspend = "N" # should be "N"
+```
+
+## Also
+
+- That could be either `btusb.enable_autosuspend=n` or `usbcore.autosuspend=-1`
+- TLP has settings for BTUSB, check it to exclude your device from autosuspend
+- There's a guy on ubuntuforums, who wrote [solution](https://ubuntuforums.org/showthread.php?t=2159645&page=6&p=12926730#post12926730), which disables autosuspend manually
+
+## Refs
+
+- [Bluetooth keyboard disconnects randomly](https://bbs.archlinux.org/viewtopic.php?id=236479)
+- [Bluetooth keeps turning off](https://bbs.archlinux.org/viewtopic.php?id=275962)
+- [ArchWiki: Device connects, then disconnects after a few moments](https://wiki.archlinux.org/title/Bluetooth#Device_connects,_then_disconnects_after_a_few_moments)
+- [Said solution with a script in rc.local](https://ubuntuforums.org/showthread.php?t=2159645&page=6&p=12926730#post12926730)